Monday

September 22, 2014

September 22, 2014

Number of results: 11,498

**Fluid Mechanics**

Oil (sp. gr.= 0.8) flows smoothly through the circular reducing section shown at 3 ft^3/s. If the entering and leaving velocity profiles are uniform, estimate the force which must be applied to the reducer to hold it in place. When Fluid is entering the pipe: P= 50 psig ...
*September 20, 2013 by Katy*

**Fluid Mechanics**

Oil (sp. gr.= 0.8) flows smoothly through the circular reducing section shown at 3 ft^3/s. If the entering and leaving velocity profiles are uniform, estimate the force which must be applied to the reducer to hold it in place. When Fluid is entering the pipe: P= 50 psig ...
*September 22, 2013 by Katy*

**Physics**

A person pushes with a horizontal force of 25 N 4kg block, initially at rest on a horizontal table, a distance of 3m. The coefficient of kinetic friction between the block and table is 0.35. determine external work on the block-table system. the energy dissipated by friction ...
*April 16, 2014 by Star *

**physics**

A 0.40kg piece of putty is dropped from a height of 2.9m above a flat surface. When it hits the surface, the putty comes to rest in 0.32s . What is the magnitude of the average force exerted on the putty by the surface? I keep getting 9.4 as the answer, but it says it's wrong...
*October 29, 2013 by Jen*

**physics**

Given that the distancef rom Earth to the Moon is 3.8 x 10^8 m, that the Moon takes 27 days to orbit Earth, and that the mass of the Moon is 7.4 x 10^22 kg, what is the acceleration of the Moon and the size of the attractive force between Earth and Moon? Use v = (2pir)/T, ...
*September 18, 2006 by Lindsay*

**Physics**

A rifle shoots a 4.1g bullet out of it's barrel. The bullet has a muzzle velocity of 975 m/s just as it leaves the barrel. Assuming a constant horizontal acceleration over a distance of 43.0 cm starting from rest, with no friction between the bullet and the barrel, what force ...
*February 20, 2014 by D*

**Physics**

The acceleration of a particle moving only on a horizontal xy plane is given by a=5ti+6tj, where a is in meters per second-squared and t is in seconds. At t=0, the position vector r=(19.0m)i+(39.0m)j locates the particle, which then has the velocity vector v=(5.70m/s)i+(3.40m/...
*March 15, 2014 by Stacey*

**physics**

A 27-kg boy stands 4 m from the center of a frictionless playground merry-go-round, which has a moment of inertia of 238 kg m2. The boy begins to run in a circular path with a speed of 0.6 m/s relative to the ground. (a) Calculate the angular velocity of the merry-go-round. (b...
*March 26, 2011 by Nick*

**physics**

A 27-kg boy stands 4 m from the center of a frictionless playground merry-go-round, which has a moment of inertia of 238 kg m2. The boy begins to run in a circular path with a speed of 0.6 m/s relative to the ground. (a) Calculate the angular velocity of the merry-go-round. (...
*March 26, 2011 by Really stuck in this problem !!*

**SCIENCE**

A conductor of length 0.5m moves in a uniform magnetic field of flux density 2 wbm. at a uniform velocity of 40m/s. Calculate the induced EMF under the following conditions: (1) the conductor moves at right angle to the magnetic field (2) the conductor moves at an angle of 30 ...
*July 26, 2014 by BNzeal*

**PHYSICS**

A conductor of length 0.5m moves in a uniform magnetic field of flux density 2 wbm^2. at a uniform velocity of 40m/s. Calculate the induced EMF under the following conditions: (1) the conductor moves at right angle to the magnetic field (2) the conductor moves at an angle of ...
*July 26, 2014 by Please help me*

**physics**

1. A cyclist maintains a constant velocity of 5.2 m/s headed away from point A. At some initial time, the cyclist is 257 m from point A. What will be his displacement from his starting position after 47 s? Answer in units of m 2.What will be his position from point A after ...
*September 13, 2011 by naia*

**physics**

A cyclist maintains a constant velocity of 6 m/s headed away from point A. At some initial time, the cyclist is 245 m from point A. What will be his displacement from his starting position after 88 s? Answer in units of m What will be his position from point A after that time...
*October 5, 2013 by hannah*

**physics**

An object travels 50 meters at 90° in 6 seconds and then travels 50 meters at 245° in 13 seconds. (a) What is the magnitude of the objects resultant displacement? (b) What is the direction of the objects resutlant displacement? (c) What is the magnitude of the objects average ...
*August 13, 2014 by Donny*

**Physics**

An arrow is shot straight upward at 55 m/s. a) find the time until the arrow reaches its peak b)how high was the arrow at its peak c)find the total time the arrow is in the air d)what was the velocity of the arrow after 3.5 seconds e)how high was it at 3.5 seconds
*December 13, 2012 by Bree*

**Physics**

An arrow is shot straight upward at 55 m/s. a) find the time until the arrow reaches its peak b)how high was the arrow at its peak c)find the total time the arrow is in the air d)what was the velocity of the arrow after 3.5 seconds e)how high was it at 3.5 seconds
*December 13, 2012 by Bree*

**Physics**

An arrow is shot straight upward at 55 m/s. a) find the time until the arrow reaches its peak b)how high was the arrow at its peak c)find the total time the arrow is in the air d)what was the velocity of the arrow after 3.5 seconds e)how high was it at 3.5 seconds
*December 13, 2012 by Bree*

**Physics**

A 23-kg boy stands 3 m from the center of a frictionless playground merry-go-round, which has a moment of inertia of 180 kg m2. The boy begins to run in a circular path with a speed of 0.6 m/s relative to the ground. (a) Calculate the angular velocity of the merry-go-round in ...
*June 18, 2012 by Maria*

**Physics**

A train travels east at a speed of 50 m/s. A passenger is walking towards the rear of the train at a speed of 3 m/s. Assume that you are standing at the train station and observing the motion of the passenger as the train passes you at the station. What is the velocity of the ...
*January 7, 2013 by Shaundrea*

**math,correction**

Can someone correct my answers thanks. Problem #1 The equation h= -16t^2+112t gives the height of an arrow, shot upward from the ground with an initial velocity of 112 ft/s, where t is the time after the arrow leaves the ground. Find the time it takes for the arrow to reach a ...
*April 5, 2007 by jasmin20*

**Physics**

At what rate must a cylindrical spaceship rotate if occupants ar to experience simulated gravity of 1/2g? Assume the spaceship's diameter is 32 m, and give your answer as the time needed for one revolution. The centripetal acceleration is R w^2, where R is the radius from the ...
*January 2, 2007 by Sam*

**physics**

A ball is thrown horizontally at 10.0 m/s from the top of a hill 50.0 m high. How far from the base of the hill would the ball hit the ground? I don't understand the following explained by Quittich (sp)? "Since there is no vertical component, the time to hit the ground is the ...
*April 2, 2008 by Jon*

**Physics 11th grade 3**

1) A box with a mass of 17 kg is moving at a velocity of 3.75 m/s. If the box was pushed with a force of 75 N how far did it go? 2) Calculate the momentum for a 0.18 kg rifle bullet traveling 369 m/s. 3) What is the impulse needed to stop the bullet? 4)Ice has a specific heat ...
*March 12, 2013 by Isis*

**Physics**

Please help me learn how to do this problem, step by step please. Engineers are developing new types of guns that might someday be used to launch satellites as if they were bullets. One such gun can give a small object a velocity of 4.1 km/s while moving it through a distance ...
*September 7, 2013 by Savannah*

**physics**

Cheetahs can sustain speeds of 25 m/s over short distances. One of their prey is Thomson's gazelle, with top speed about 22 m/s. If a 52kg cheetah running southward at top speed grabs and holds onto a 23kg gazelle running westward at 22 m/s, find the velocity of these animals ...
*February 25, 2014 by blake*

**Physics **

A box of mass 1.50 kg is given an initial velocity of 12.5 m/s up an inclined ramp that makes an angle of 25.0o with the ground, which is horizontal. The coefficient of kinetic friction between the box and the ramp is 0.240. How long does the box slide up the ramp before it ...
*May 13, 2014 by Tyler*

**Physics **

A box of mass 1.50 kg is given an initial velocity of 12.5 m/s up an inclined ramp that makes an angle of 25.0o with the ground, which is horizontal. The coefficient of kinetic friction between the box and the ramp is 0.240. How long does the box slide up the ramp before it ...
*May 13, 2014 by Tom*

**physics**

A bullet of mass = 0.13 kg is fired with a velocity of = 87.1 m/s into a solid cylinder of mass = 17.1 kg and radius = 0.29 m. The cylinder is initially at rest and is mounted on a fixed vertical axis that runs through its center of mass. The line of motion of the bullet is ...
*April 2, 2008 by shelby*

**calculus**

Consider a gun fired from a tower 96ft above the ground. The angle of elevation of the gun is 60 degrees, and its muzzle velocity is 1600 ft/sec (also gravity in this equation is 32 ft/sec^2). a)When does the bullet hit the ground? b)Write a parametric equation that models the...
*August 13, 2011 by jessica*

**Physics**

A 50 kg skater at rest on a frictionless rink throws a 2 kg ball, giving the ball a velocity of 10 m/s. Which statement describes the skaters subsequent motion? Explain please. a. 0.4 m/s in the same direction as the ball. b. 0.4 m/s in the opposite direction of the ball. c. 2...
*December 2, 2012 by Alexa*

**science**

You throw a vall toward a wall with a speed of 25m/s and at an angleof 40 degree above the horizontal. The wall is 22m from the realease point of the ball. a) How far above the release point does the ball hit the wall? b) What are the horizontal and vertical components of its ...
*October 24, 2006 by Jose*

**Repost physics**

Suppose the position of an object is given by ->r(vector) = (3.0t^2*ihat - 6.0t^3*jhat)m. Where t in seconds. Determine its velocity ->v as a function of time t. Determine its acceleration ->a as a function of time t. Determine ->r at time t = 2.5 s. Determine ->...
*September 15, 2009 by Han*

**Physics**

You swing a 5.9 kg bucket of water in a vertical circle of radius 0.3 m. (a) What speed must the bucket have if it is to complete the circle without spilling any water? (b) How does your answer depend on the mass of the bucket? a) I don't understand how the velocity can be ...
*February 14, 2010 by Bob C*

**Physics, help please!!!**

A tank is fillwed with 0.7m of water, a hole at the bottum of the tank with a radius of 0.001m is opened. At the same time, water is added to the tank at the same rate as it exits, calculate the speed at which water flows out from the hole. I am using P=Po+pgh which gives me ...
*March 18, 2010 by Dave*

**physics**

A ship maneuvers to within 2500m of an island's 1800m high mountain peak and fires a projectile at an enemy ship 610m on the other side of the peak. If the ship shoots the projectile with an initial velocity of 250m/s at an angle of 75 degrees. how close to the enemy ship does...
*October 8, 2010 by Sydney*

**physics**

A passenger on a stopped bus notices that rain is falling vertically just outside the window. When the bus moves with constant velocity, the passenger observes that the falling raindrops are now making an angle of 18 with respect to the vertical. What is the ratio of the speed...
*September 5, 2011 by cassie*

**college physics**

When a projectile lands, the angle made between the projectile and the ground corresponds to which of the following aspects of its motion? a)the direction of the acceleration vector just before impact b)direction of the velocity vector just before impact c)direction of the ...
*April 18, 2012 by CLARE*

**college physics**

When a projectile lands, the angle made between the projectile and the ground corresponds to which of the following aspects of its motion? a)the direction of the acceleration vector just before impact b)direction of the velocity vector just before impact c)direction of the ...
*April 18, 2012 by CLARE*

**college physics**

Topic: Relative Velocity Question: The escalator that leads down into a subway station has a length of 30.0 m and a speed of 1.8 m/s relative to the ground. A student is coming out of the station by running in the wrong direction on this escalator. The local record time for ...
*February 1, 2009 by John*

**physics**

a rock is thrown horizontally with a speed of 17 m/s from a vertical cliff of height 34 m. A- I solved for t=2.63 B-How far will it land from the base of the cliff? im using x=xo+vox*t i get -6.46 and it is wrong. What am I doing wrong? C-What is the velocity (magnitude and ...
*September 6, 2010 by tommy *

**math**

A stone is thrown straight up from the edge of a roof, 700 feet above the ground, at a speed of 10 feet per second. (A). Remembering that the acceleration due to gravity is -32 feet per second squared, how high is the stone 2 seconds later? Don't forget to enter correct units...
*October 7, 2010 by Viky*

**physics**

As soon as a traffic light turns green, a car speeds up from rest to 46.0 mi/h with constant acceleration 8.50 mi/h-s. In the adjoining bike lane, a cyclist speeds up from rest to 24.0 mi/h with constant acceleration 12.00 mi/h-s. Each vehicle maintains constant velocity after...
*February 10, 2011 by james*

**Physics**

In a slow-pitch softball game, a 0.200 kg softball crossed the plate at 10.00 m/s at an angle of 45.0° below the horizontal. The batter hits the ball toward center field, giving it a velocity of 44.0 m/s at 30.0° above the horizontal. If the force on the ball increases ...
*November 2, 2011 by Eddy*

**Physics**

12th grade physics ap question. A baseball with a mass of 120 g is hit 21.8 m into the air. The ball is caught by the third baseman 2.5 m above the ground. What potential energy did the ball develop at its highest point? How much potential energy did it still have when it was ...
*October 24, 2012 by Ravin*

**Physics**

Which of the following statements is not true about refraction? Refraction occurs when light's velocity changes. The angle between the refracted ray and the normal is called the angle of refraction. When light moves from a rarer to a denser medium, it bends toward the normal. ...
*October 26, 2012 by What?*

**Physics**

Which of the following statements is not true about refraction? Refraction occurs when light's velocity changes. The angle between the refracted ray and the normal is called the angle of refraction. When light moves from a rarer to a denser medium, it bends toward the normal. ...
*October 26, 2012 by Nerm*

**physics**

The waterfall "Angel Falls" in Venezuela is the world's tallest at h=979 m. Assume that the water's velocity on the top of the falls and on the bottom of the falls (after it hits the ground and begins to flow away) is equal, and that no total energy is lost by the water to the...
*February 11, 2013 by please help me out!!! please*

**physics!**

The waterfall "Angel Falls" in Venezuela is the world's tallest at h=979 m. Assume that the water's velocity on the top of the falls and on the bottom of the falls (after it hits the ground and begins to flow away) is equal, and that no total energy is lost by the water to the...
*February 13, 2013 by please help me out!!!!*

**physics.........**

The waterfall "Angel Falls" in Venezuela is the world's tallest at h=979 m. Assume that the water's velocity on the top of the falls and on the bottom of the falls (after it hits the ground and begins to flow away) is equal, and that no total energy is lost by the water to the...
*February 14, 2013 by please help me out!!!!*

**Physics**

As soon as a traffic light turns green, a car speeds up from rest to 45.0 mi/h with constant acceleration 8.50 mi/h/s. In the adjoining bike lane, a cyclist speeds up from rest to 15.0 mi/h with constant acceleration 12.50 mi/h/s. Each vehicle maintains constant velocity after...
*September 7, 2013 by Anonymous*

**Physics**

A slotted disk is rotating with a constant angular velocity of w. A ball mass of m slides out from the center of the disk. Kinetic friction force F=mu_k |N| acts on the mass, where N is the normal force between the ball and the channel. Using the body coordinate system i^, j^ ...
*November 11, 2013 by Joldox*

**Physics Quick!**

An archer shoots an arrow with a velocity of 49.5 m/s at an angle of 52.0¡Æ with the horizontal. An assistant standing on the level ground 150 m downrange from the launch point throws an apple straight up with the minimum initial speed necessary to meet the path of the arrow...
*August 19, 2012 by kk2*

**physics**

A 48 kg skier starts from rest at a height of H = 28 m above the end of the ski-jump ramp. As the skier leaves the ramp, his velocity makes an angle of 28° with the horizontal. Neglect the effects of air resistance and assume the ramp is frictionless. (a) What is the maximum ...
*November 2, 2012 by joshwa*

**physics**

The Pacific Crest Trail runs from the Mexican border to the Canadian border through California, Oregon, and Washington,covering 2650 miles of trail, but only about 1000 straight-line miles. B).If you hike this trail in 14.0 weeks, from Mexico to Canada,find your average ...
*January 26, 2011 by mely*

**Physics**

The prong of a tuning fork moves back and forth when it is set into vibration. The distance the prong moves between its extreme positions is 2.28 mm. If the frequency of the tuning fork is 440.6 Hz, what are the maximum velocity and the maximum acceleration of the prong? ...
*March 30, 2012 by Riya*

**math**

The height of a rocket in meters t seconds after it is launched is approximated by the polynomial 0.5 at2 + vt + y where a is always -9.8, v is the initial velocity, and h is the initial height. A 300X was launched from a height of 10 meters. What was its height after 3 seconds?
*August 16, 2010 by jacob*

**Physics**

A person is a playing a game that requires throwing an object onto a ledge. The ledge is a distance d and a height d/2 above the release point. You may neglect air resistance. You may use g for the magnitude of the gravitational acceleration (i.e. g=9.81m/s2). (a) At what ...
*September 22, 2013 by ss01*

**Physics**

A skier is pulled up a slope at a constant velocity by a tow bar. The slope is inclined at 24.0° with respect to the horizontal. The force applied to the skier by the tow bar is parallel to the slope. The skier's mass is 60.0 kg, and the coefficient of kinetic friction between...
*February 3, 2011 by Lauren*

**physics**

A skier is pulled up a slope at a constant velocity by a tow bar. The slope is inclined at 25.9° with respect to the horizontal. The force applied to the skier by the tow bar is parallel to the slope. The skier's mass is 55.3 kg, and the coefficient of kinetic friction between...
*January 28, 2012 by rachel *

**physics **

A skier is pulled up a slope at a constant velocity by a tow bar. The slope is inclined at 25.9° with respect to the horizontal. The force applied to the skier by the tow bar is parallel to the slope. The skier's mass is 55.3 kg, and the coefficient of kinetic friction between...
*January 30, 2012 by Amanda *

**physics**

A skier is pulled up a slope at a constant velocity by a tow bar. The slope is inclined at 25.9° with respect to the horizontal. The force applied to the skier by the tow bar is parallel to the slope. The skier's mass is 55.3 kg, and the coefficient of kinetic friction between...
*January 30, 2012 by Marlee *

**physics**

A skier is pulled up a slope at a constant velocity by a tow bar. The slope is inclined at 22.2° with respect to the horizontal. The force applied to the skier by the tow bar is parallel to the slope. The skier's mass is 56.0 kg, and the coefficient of kinetic friction between...
*September 28, 2012 by shyne*

**Physics**

A Block weighing 72.2 N rests on a plane inclined at 20.0 deg. to the horizontal. The coefficients of static and kinetic friction are 0.22 and 0.12 resp. What is the minimum magnitude of F that will start the block moving up the plane? (I also got 9,74 N for this.. but wrong ...
*September 29, 2007 by Lily*

**Physics**

A 9.60 g coin is placed 10.7 cm from the center of a turntable. The coin has a coefficient of static friction of 0.80 and a coefficient of kinetic friction of 0.60 with the turntable. The turntable's angular velocity slowly speeds up until the coin starts to slide off. ...
*October 17, 2011 by Dan*

**Physics**

A 6.80 g coin is placed 10.0 cm from the center of a turntable. The coin has a coefficient of static friction of 0.80 and a coefficient of kinetic friction of 0.60 with the turntable. The turntable's angular velocity slowly speeds up until the coin starts to slide off. ...
*October 17, 2011 by Helpp*

**physics**

A baseball player hits a home run over the left-field fence, which is 104 m from home plate. The ball is hit at a point 1.04 m directly above home plate, with an initial velocity directed 28.5° above the horizontal. By what distance does the baseball clear the 3.00 m high ...
*October 16, 2012 by Anthony *

**physics**

A diver runs and dives off the end of a spring board that is 0.9 meters above the surface of the water. As she takes off from the diving board, her velocity is 5.2 m/s directed 36° above horizontal calculate: a) the time she is in the air s b) the distance she lands from the ...
*October 29, 2012 by Mat*

**Physics**

The goblins fists cut through the air and connects with the dwarfs face in an elastic collision. The goblins fists each weigh 2kg and the dwarfs head weighs 5kg. What is the kinetic energy imparted to the dwarfs face by the goblins fists if the goblins fists had an initial ...
*January 22, 2014 by Jakezzz*

**Physics**

A bicycle chain is wrapped around a rear sprocket (r = 0.038 m) and a front sprocket (r = 0.11 m). The chain moves with a speed of 1.6 m/s around the sprockets, while the bike moves at a constant velocity. Find the magnitude of the acceleration of a chain link that is in ...
*October 26, 2010 by Zaphod*

**physics**

River A & B flow into river C. River A is 40 ft wide and is flowing at an average of 2.47 mph. River B is 25 ft wide and has a flow rate of 1125 cubic feet per second. Assume all rivers have a uniform depth of 15 ft. If river C is 100 ft wide, what is its average velocity [...
*October 19, 2011 by Brian*

**Physics**

A crate of mass 29 kg is pushed up a ramp by a person as shown in the figure below. The person pushes the crate a distance of 25 m as measured along the ramp. Assume the crate moves at constant velocity. Assume the coefficient of kinetic friction between the crate and the ramp...
*July 11, 2012 by Sierra*

**physics**

A bicycle chain is wrapped around a rear sprocket (r = 0.041 m) and a front sprocket (r = 0.15 m). The chain moves with a speed of 1.4 m/s around the sprockets, while the bike moves at a constant velocity. Find the magnitude of the acceleration of a chain link that is in ...
*November 10, 2013 by Anonymous*

**physics**

1.A car is traveling a road that includes two sides of an equilateral triangle with a constant speed s. What is the magnitude of the average velocity v of the car? 2.A ship crosses a river aiming at the angle theta to the left from the straight courses. The speed of the ship ...
*March 9, 2011 by sandhu*

**physics**

1.A car is traveling a road that includes two sides of an equilateral triangle with a constant speed s. What is the magnitude of the average velocity v of the car? 2.A ship crosses a river aiming at the angle theta to the left from the straight courses. The speed of the ship ...
*March 9, 2011 by sandhu*

**engineering**

A slotted bar is attached to the origin and rotates in the horizontal plane with a constant angular velocity of 0.665 radians/s . The bar moves a roller weighing 33.6 lb along the cam's perimeter. A spring holds the roller in place; the spring's spring constant is 1.34 . The ...
*October 11, 2011 by HELP PLEASE! DOn't know How to do it!!! :(*

**computer network engineering**

a steel ball weighing 128 lb is suspended from a spring, whereupon the spring is stretched 2 ft from its natural length. the ball is started in motion with no initial velocity by displacing it 6 in above the equilibrium position. assuming no damping force, find an expression ...
*April 22, 2012 by anisah*

**physics**

A stationary rocket is launched vertically upward. After 4s, the rocket's fuel is used up and it is 225.6 m above the ground. At this instant the velocity of the rocket is 112,8 m/s. Then the rocket undergoes free fall. Ignore the effect of the air friction.Assume that g does ...
*March 8, 2014 by clement*

**physics**

In Figure 20.2 is a velocity selector that can be used to measure the speed of a charged particle. A beam of particles is directed along the axis of the instrument. A parallel plate capacitor sets up an electric field E which is oriented perpendicular to a uniform magnetic ...
*April 23, 2014 by Anonymous*

**College Physics**

Two children are playing on a 178.2 m tall bridge. One child drops a rock (initial velocity zero) at t = 0 . The other waits 2.7 s and then throws a rock downward with an initial speed v0. If the two rocks hit the ground at the same time, what is v0 ? for the first rock i ...
*September 11, 2011 by Anon14*

**Physics - KE**

In Figure 11-32 (which shows a ball at the top of an incline, at the bottom of the incline a loop begins with radius R and Q a point on the loop lined up with the center of the loop), a solid brass ball of mass m and radius r will roll without slipping along the loop-the-loop...
*March 27, 2007 by COFFEE*

**Physics - Forces**

A 42kg girl jumps on a trampoline, after stretching to its bottom limit; the trampoline exerts an average upward force on the girl over a diplacement of 0.50m. During the time that the trampoline is pushing her up, se experiences an average acceleration of 65.0m/s^2. Her ...
*August 24, 2010 by Shaila*

**Physics**

Find Acceleration and velocity of vault or car(from rest). This is info from the movie Fast 5(Vault Heist). time = 15s Vault ≈ 74,750 lb ≈ 33,903.03 kg Car ≈ 1900 kg Money in vault ≈ 4,900 kg Estimate coefficient (tires & concrete) ≈ 1 Estimate ...
*April 17, 2014 by Renee ( PLEASE HELP ME)*

**College Physics**

A skier is pulled up a slope at a constant velocity by a tow bar. The slope is inclined at 28.2 ° with respect to the horizontal. The force applied to the skier by the tow bar is parallel to the slope. The skier's mass is 46.7 kg, and the coefficient of kinetic friction ...
*March 15, 2012 by Angela*

**algebra**

A model rocket is launched upward with an initial velocity of 200 feet per second. The height, in feet, of the rocket t seconds after the launch is given by h = −16t2 + 200t. How many seconds after the launch will the rocket be 380 feet above the ground? Round to the ...
*September 14, 2014 by Nate*

**Physics**

1. A certain playground merry-go-round is essentially an 90-kg iron disk 2.0 m in radius. Two children, each with a mass of 46 kg, are originally standing on opposite sides of the disk near its outer edge. The merry-go-round is turning essentially without friction about a ...
*May 6, 2011 by Jordan*

**BIOLOGY**

1.Which of the following principles is not part of Darwin's theory of evolution by natural selection? Individuals with the most favorable traits have the best chance of reproducing. More individuals are born than will be able to survive. Mutations are the ultimate source of ...
*September 25, 2012 by batmo*

**-MATH-**

h=-16t2+80t+96 Use this position polynomial to calculate the following: 1.The height of the object after 2 seconds 2.The height of the object after 4 seconds 3.How long the object will take to reach the ground? 4.Write the position function for an object that is thrown upward ...
*December 2, 2013 by Steph*

**Physics**

A hockey puck slides along the ice. There is a frictional force between the ice and puck, and this is the only horizontal force on the puck. Which of the following must be true? A. The puck will slow down and eventually come to rest. B. The puck will continue to move at ...
*December 8, 2011 by Anonymous*

**AP Physics**

An airplane in a horizontal circle at a speed of 130.5556 m/s. If its wings are tilted 40 degress to teh horizontal, what is the radius of the circle in which the plane is flying? Assume that the required force is provided entirely by an "aerodynamic lift" that is ...
*October 28, 2007 by Kristen*

**Physics**

A 14000 N automobile travels at a speed of 50 km/h northward along a street, and a 7500 N sports car travels at a speed of 62 km/h eastward along an intersecting street. (a) If neither driver brakes and the cars collide at the intersection and lock bumpers, what will the ...
*November 24, 2010 by Jen*

**Physics**

A 14000 N automobile travels at a speed of 50 km/h northward along a street, and a 7500 N sports car travels at a speed of 62 km/h eastward along an intersecting street. (a) If neither driver brakes and the cars collide at the intersection and lock bumpers, what will the ...
*November 24, 2010 by Sandi*

**college physics**

In Physics we often use meters per second as the units of velocity, rather than miles per hour. Convert 1 meter per second to miles per hour to get an idea of how these units compare. Please help me by showing me step by step so I can understand it better.
*September 21, 2008 by Yvonne*

**Algebra**

A baseball player hits a baseball into the air with an initial vertical velocity of 48 feet per second from a height of 3 feet. 8. Write an equation that gives the baseball’s height as a function of the time (in seconds) after it is hit. 9. After how many seconds does the ...
*March 31, 2013 by Elizabeth*

**phy**

1 An object is thrown upward from the edge of a tall building with a velocity of 10 m/s. Where will the object be 3 s after it is thrown? Take g=10ms−2 15 m above the top of the building 30 m below the top of the building 15 m below the top of the building 30 m above the...
*January 28, 2013 by christ*

**Math-**

A ball is thrown vertically upward with an initial velocity of 96 feet per second. The distance s (in feet) of the ball from the ground after t seconds is s(t)=96t-16t^2 a.) at what time will the ball strike the ground b.) for what time t is the ball more than 128 feet above ...
*March 25, 2012 by danielle*

**Physics **

A rope exerts a constant horizontal force of 203N pulling a 68-kg crate across the floor. The velocity of the crate is observed to increase from 3m/s to 5m/s in a time of 4 seconds under the influence of this force and the frictional force exerted by the floor on the crate. ...
*June 21, 2013 by Tim *

**physical**

From t = 0 to t = 3.30 min, a man stands still, and from t = 3.30 min to t = 6.60 min, he walks briskly in a straight line at a constant speed of 1.76 m/s. What are (a) his average velocity vavg and (b) his average acceleration aavg in the time interval 1.00 min to 4.30 min? ...
*September 20, 2012 by Aa*

**physical**

From t = 0 to t = 3.30 min, a man stands still, and from t = 3.30 min to t = 6.60 min, he walks briskly in a straight line at a constant speed of 1.76 m/s. What are (a) his average velocity vavg and (b) his average acceleration aavg in the time interval 1.00 min to 4.30 min? ...
*September 20, 2012 by Aa*

**math**

The kinectic energy E, of a toy car is directly proportional to the square of its velocity v. The difference in the kinectic energy of the toy car when it is travelling at 15cm/s and 20cm/s in 10 J. Find the kinectic energy of the toy car when it is travelling at 12cm/s thanks :)
*June 11, 2012 by Vinitha*

**PHYSICS : )**

A flight attendant pulls her 69.1 N flight bag a distance of 280 m along a level airport floor at a constant velocity. The force she exerts is 32.7 N at an angle of 50.2◦ above the horizontal. Find the work done by the force of friction on the flight bag. Answer in units...
*October 18, 2008 by Jay*

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