Saturday

April 18, 2015

April 18, 2015

Number of results: 21,822

**physics**

a shopper in a supermarket pushes a cart with a force of 35 n directed at an angle of 25 downward from the horizontal. the force is just sufficient to over come the various frictional force, so the cart moves at constant speed. what is the net work dont on the cart? why? the ...
*September 23, 2010 by physics help please!!!*

**Astrophysics**

You know M(r) = v^2r /G d = distance; s= speed Planet 1: d=2/s=120 Planet 2: d=4/s=60 Planet 3: d=9/s=40 Planet 4: d=16/s=30 Planet 5: d=36/s = 20 You use the distance and orbital speed of the first planet to determine the mass enclosed within the orbit of the first planet to ...
*October 29, 2008 by anonymous*

**Physics**

An open-topped tank completely filled with water has a release valve near its bottom. The valve is 1.75m below the water surface. Water is released from the valve to power a turbine, which generates electricity. The area of the top of the tank, AT, is 11.5 times the cross-...
*September 3, 2014 by Santi*

**physics**

The speed of a bullet as it travels down the barrel of a rifle toward the opening is given by v = (-4.25 107) t 2 + (3.45 105) t, where v is in meters per second and t is in seconds. The acceleration of the bullet just as it leaves the barrel is zero. (a) Determine the ...
*January 22, 2015 by Anonymous*

**physics**

A bullet with mass m = 5.21 g is moving horizontally with a speed v=367 m/s when it strikes a block of hardened steel with mass M = 14.8 kg(initially at rest). The bullet bounces o the block in a perfectly elastic collision. (a) What is the speed (m/s) of the block immediately...
*December 15, 2011 by Sarah*

**physics**

Traffic shock wave. An abrupt slowdown in concentrated traffic can travel as a pulse, termed a shock wave, along the line of cars, either downstream (in the traffic direction) or upstream, or it can be stationary. Figure 2-22 shows a uniformly spaced line of cars moving at ...
*October 10, 2011 by turk*

**physics i really need help :(**

A projectile is fired with an initial speed of 61.3m/s at an angle of 31.5° above the horizontal on a long flat firing range. a)Determine the maximum height reached by the projectile. b)Determine the total time in the air. c)Determine the total horizontal distance covered (...
*November 24, 2012 by juanita*

**physics**

Two gears A and B are in contact. The radius of gear A is twice that of gear B. (a) when A’s angular velocity 6.00 Hz counter clockwise, what is B’s angular velocity? (b) If A’s radius to the tip of the teeth is 10.0 cm what is the linear speed of a point on the tip of a gear ...
*October 3, 2011 by John*

**math**

Two towns P and Q are 400 km apart. A bus left for P and Q. It stopped at Q for one hour and then started the return to P. one hour after the departure of the bus from P, a trail also heading for Q left P. the trailer met the returning bus ¾ of the way from P to Q. they met t ...
*March 14, 2015 by kudu*

**math**

Two towns P and Q are 400 km apart. A bus left for P and Q. It stopped at Q for one hour and then started the return to P. one hour after the departure of the bus from P, a trail also heading for Q left P. the trailer met the returning bus ¾ of the way from P to Q. they met t ...
*March 15, 2015 by kudu*

**general science**

2 waves are traveling through a container of nitrogen gas. Amplitude of the first wave is 0.3 cm, and the second 0.9 cm. What is true about the two waves? a. the energy of thee first wave is less than the second b. energy of the first wave is greater c. speed of the first wave...
*February 26, 2010 by Mike*

**physics help**

A 1100 kg automobile is at rest at a traffic signal. At the instant the light turns green, the automobile starts to move with a constant acceleration of 3.0 m/s2. At the same instant a 2800 kg truck, traveling at a constant speed of 8.0 m/s, overtakes and passes the automobile...
*March 26, 2010 by beav*

**Physics - sound waves**

I listed the questions with my answers. Are the answers correct? Thanks. A railroad locomotive is a rest with its whistle shrieking, and then it starts moving toward you. a.) Does the frequency that you hear increase, decrease, or stay the same? The frequency of the waves ...
*October 17, 2009 by Mary*

**Math**

The Pioneer 10 spacecraft passed the planet Jupiter on December 12, 1973, and exited the solar system on June 14, 1983. The craft traveled from Mars to Jupiter, a distance of approximately 1 billion kilometers, in one year and nine months. a.Calculate the approximate speed of ...
*November 17, 2013 by Aubrey*

**Displacement and Velocity**

A turtle moves 3.5m [E] in 136 s and then moves 1.7m [W] in 88 s. a) What is the average speed of the turtle? b) What is the average velocity of the turtle? average speed: D/T = 3.5m + 1.7m = 5.2m/ 224s = 0.024m/s average velocity:??????????/
*November 13, 2010 by Anonymous*

**Physics**

Two pucks collide on a level air-hockey table. Puck A has a mass of 0.0250 kg and is moving initially due eastward at a speed of 5.50m/s. Puck B has a mass of 0.0500kg and is initially at rest. Right after collision, puck A is moving in a direction of 65 degrees north of east...
*November 2, 2009 by John*

**Physics**

A 15.0 m long truck traveling at 40.0 mph has a braking capability of 5.00 m/s2 from this speed. It is approaching a 10.0-m wide intersection with a traffic light that is turning yellow. (a) What is the minimum distance the truck can be from the intersection if the truck is to...
*January 23, 2013 by Help Me*

**Physics Help Please**

Suppose you work at an amusement park. Your boss has asked you to determine the "people current," a measurement of moving people coming through the entrance of the park. a) what would be the units of "people current?" b) what information would "people current" provide? c) ...
*February 11, 2015 by Help!*

**Physics Help Please!**

Suppose you work at an amusement park. Your boss has asked you to determine the "people current," a measurement of moving people coming through the entrance of the park. a) what would be the units of "people current?" b) what information would "people current" provide? c) ...
*February 11, 2015 by Help!*

**Physics**

A man stands on a platform that is rotating (without friction) with an angular speed of 1.21 rev/s; his arms are outstretched and he holds a brick in each hand The rotational inertia of the system consisting of the man, bricks, and platform about the central axis is 4.32 kg·m2...
*November 18, 2011 by Aimee*

**physics**

A 120 kg mass is blown apart into an 80 kg piece and 40 kg piece. after the blast, the two masses are moving apart with a relative velocity of 60 m/s. the total kinetic energy after the explosion is: A. 21 kJ B. 35 kJ C. 48 kJ D. 56 kJ E. 82 kJ Because of momentum conservation...
*August 6, 2007 by mandy*

**Physics 141**

A satellite is in a circular orbit around an unknown planet. The satellite has a speed of 1.60 104 m/s, and the radius of the orbit is 5.50 106 m. A second satellite also has a circular orbit around this same planet. The orbit of this second satellite has a radius of 8.50 106 ...
*February 21, 2014 by Hope*

**Physics 141**

A satellite is in a circular orbit around an unknown planet. The satellite has a speed of 1.60 104 m/s, and the radius of the orbit is 5.50 106 m. A second satellite also has a circular orbit around this same planet. The orbit of this second satellite has a radius of 8.50 106 ...
*February 21, 2014 by Hope*

**Physics**

In this section assume the sound speed in air is 343 m/s. A goose flying toward you at 12.6m/s emits a squawk, which you hear at 258Hz . A)Find the wavelength of the sound you hear B)Find the wavelength of the sound you hear if the goose emits the same squawk while flying away...
*December 2, 2013 by sandra*

**Physics**

With what speed relative to the rocks does the clam smash into the rocks? and With what speed relative to the gull does the clam smash into the rocks?
*September 20, 2012 by Lisa*

**Physics**

A stone is thrown from the edge of a cliff into the ocean below. It is thrown somewhat upward, but mostly outward. The stone has a mass of 2.0kg and is thrown with a speed of 10m/s from an initial height of 5.0m above the ocean. A. What is the kinetic energy of the stone when ...
*April 1, 2013 by Jay*

**Physics**

A stone is thrown from the edge of a cliff into the ocean below. It is thrown somewhat upward, but mostly outward. The stone has a mass of 2.0kg and is thrown with a speed of 10m/s from an initial height of 5.0m above the ocean. A. What is the kinetic energy of the stone when ...
*April 1, 2013 by Jay*

**Physics**

A hare and a tortoise compete in a race over a course 1.20 km long. The tortoise crawls straight and steadily at its maximum speed of 0.540 m/s toward the finish line. The hare runs at its maximum speed of 9.00 m/s toward the goal for 0.800 km and then stops to taunt the ...
*October 9, 2009 by Chloe*

**physics**

A hare and a tortoise compete in a race over a course 4.90 km long. The tortoise crawls straight and steadily at its maximum speed of 0.440 m/s toward the finish line. The hare runs at its maximum speed of 14.00 m/s toward the goal for 0.800 km and then stops to tease the ...
*September 9, 2012 by Kit*

**physics**

police officer in a patrol car parked in a 70km/h zone observe a passing automobile travelling at a slow. constant speed. believing that of the automobile might be intoxicated the officer starts his car acceleration uniformly to 9km/h in 8s. and maintaining a constant velocity...
*October 17, 2013 by abdul*

**math-word problem**

A plane flies with a ground speed of 160 miles per hour if there is no wind. It travels 350 miles with a head wind and in the same time it takes to go 450 miles with a tail wind. Find the speed of the wind. I'm pretty bad with word problems, but this is how I answered it: set ...
*May 6, 2008 by Jennifer*

**Physics**

To stop a car, you require first a certain reaction time to begin braking. Then the car slows under the constant braking deceleration. Suppose that the total distance moved by your car during these two phases is 56.7 m when its initial speed is 80.0 km/h, and 24.4 m when the ...
*October 3, 2010 by Bob*

**Physics ~ CONSERVATION OF MOMENTUM~**

1.) A 10,000 kg railroad car traveling at a speed of 24.0 m/s strikes an identical car at rest. If the cars lock together as a result of the collision, what is their common speed afterward? 2.) A 3.0 kg ball at 3 m/s and strikes a 1.5 kg ball moving at -2 m/s. After the ...
*February 18, 2013 by Isis*

**Physics **

A train traveling at a speed of 110 km/h uniformly decelerates for 20 seconds. During that time it travels 450m. A) What is the acceleration? (m/s^2) B) What is its speed after deceleration? (km/h) A ANS = -.805m/s^2 B ANS = 52km s = 450m t = 20 seconds u = 110km/h*1000m/km /...
*January 11, 2014 by Danny*

**Calculus**

Astronomers have a mathematical model for the orbital speed of the stars as a function of their distance x from the center of the galaxy: V(x) = 350x/(1+(x^2))^(3/4) where x = 1 for 10,000 light years, x = 2 for 20,000 light years. At a distance of 10,000 light years, the ...
*January 24, 2012 by Scooby10*

**physics**

Two stones, A and B, are thrown horizontally from the top of a cliff. Stone A has an initial speed of 15 meters per second and stone B has an initial speed of 30 meters per second. Compared to the time it takes stone A to reach the ground, the time it takes stone B to reach ...
*November 18, 2013 by Anonymous*

**physics**

A house with its own well has a pump in the basement with an output pipe of inner radius 6.4 mm. Assume that the pump can maintain a gauge pressure of 420 kPa in the output pipe. A showerhead on the second floor (7.5 m above the pump's output pipe) has 38 holes, each of radius...
*April 9, 2012 by Angelina*

**physics**

In a World Cup soccer match, Juan is running due north toward the goal with a speed of 7.80 m/s relative to the ground. A teammate passes the ball to him. The ball has a speed of 13.6 m/s and is moving in a direction of 32.5 degrees east of north, relative to the ground. a)...
*November 2, 2010 by bobjahng*

**physics**

An ice skater spins about a vertical axis at an angular speed of 15 rad s−1 when her arms are outstretched. She then quickly pulls her arms into her sides in a very small time interval so that the frictional forces due to ice are negligible. Her initial moment of inertia...
*March 15, 2012 by swapnali*

**physics**

A certain truck can slow at a maximum rate of 4.6 m/s2 in an emergency. When traveling in this truck at a constant speed of 19 m/s the driver spots a large hole in the road 48.2 m in from of his position. The truck continues moving forward at a constant speed until the driver ...
*September 22, 2013 by lanaaaaaa*

**science**

A gear with 30 teeth turns a gear with 5 teeth. How many turns will the driven gear turn for every turn the drive gear makes? Is this type of gear train usedto increase force or speed and distance? The tumber of teeth engaged is the same for both gears, but 30 teeth (1 turn) ...
*March 27, 2007 by kelly5*

**physics college**

An antelope moving with constant acceleration covers the distance between two points 70.0 m apart in 7.00 s. Its speed as it passes the second point is 15.0 m/s. (a) What is its speed at the first point? (b) What is its acceleration? A car is stopped at a traffic light. It ...
*October 8, 2010 by meera*

**PHYSICS**

A roller coaster powered by a spring launcher follows a frictionless track as shown below. The roller coaster cart has a mass of 500 kg, and the spring launcher has a spring constant of 1500 N/m. a. If the cart starts at a height h1 = 10m, how much must the spring be ...
*February 12, 2014 by Sarah*

**physics **

A race car is able to accelerate at a rate of 14m/s2. After exiting a turn at a speed of 15m/s, the car enters a straightaway and accelerates to a speed of 96m/s just as it reaches the end of the straightaway and enters the next turn. A)how long did it take the car to ...
*July 18, 2011 by Edward*

**Physics**

Jack and Jill are skating. Jill has a mass of 50 kg, Jack has a mass of 80 kg. At t=0 seconds Jill starts skating across a 50 m diameter rink at a speed of 3 m/s. After 3 seconds Jack skates after her with a speed of 5 m/s. When they meet, Jack scoops up Jill and they glide to...
*May 13, 2013 by Hale*

**math**

One train left the station and traveled toward its destination at a speed of 65 miles per hour. Later, another train left the station traveling in the opposite direction of the first train, it was going at a speed of 75 miles per hour. After the first train had traveled for 14...
*May 23, 2013 by jake*

**physics**

A uranium nucleus 238U may stay in one piece for billions of years, but sooner or later it decays into an a particle of mass 6.64×10^−27 kg and 234Th nucleus of mass 3.88 × 10^−25 kg, and the decay process itself is extremely fast(it takes about 10^−20 s). ...
*January 16, 2010 by Anonymous*

**physics**

Two tanks are engaged in a training exercise on level ground. The first tank fires a paint-filled training round with a muzzle speed of 250 m/s at 10.0◦ above the horizontal while advancing toward the second tank with a speed of 15.0 m/s relative to the ground. The ...
*October 5, 2014 by Anonymous*

**math**

At an airport, a flight controller was in a tower 40m above the ground. When she first observed a plane it was at an angle of elevation of 12 (degrees) from her line of sight and flying at a constant altitude (height) The plane had a constant speed of 360km/h Eight seconds ...
*May 19, 2013 by alice*

**Physics**

A truck on a straight road starts from rest and accelerates at 2.8 m/s^2 until it reaches a speed of 16 m/s. Then the truck travels for 16s at constant speed until the brakes are applied,stopping the truck in a uniform manner in an additional 3.6 s. How long is the truck in ...
*September 9, 2014 by Isaac*

**physics**

A person is riding on a flatcar traveling at a constant speed v1= 15 m/s with respect to the ground. He wishes to throw a ball through a stationary hoop in such a manner that the ball will move horizontally as it passes through the hoop. The hoop is at a height h=4 m above his...
*October 4, 2013 by leonard*

**physics**

Two arrows are shot vertically upward. The second arrow is shot after the first one, but while the first is still on its way up. The initial speeds are such that both arrows reach their maximum heights at the same instant, although these heights are different. Suppose that the...
*August 26, 2012 by Anonymous*

**Physics**

Two arrows are shot vertically upward. The second arrow is shot after the first one, but while the first is still on its way up. The initial speeds are such that both arrows reach their maximum heights at the same instant, although these heights are different. Suppose that the...
*August 31, 2012 by Marissa*

**physics**

Two arrows are shot vertically upward. The second arrow is shot after the first one, but while the first is still on its way up. The initial speeds are such that both arrows reach their maximum heights at the same instant, although these heights are different. Suppose that the...
*September 5, 2012 by Tracie *

**physics**

A 316-kg boat is sailing 12.0° north of east at a speed of 1.60 m/s. 39.0 s later, it is sailing 36.0° north of east at a speed of 4.00 m/s. During this time, three forces act on the boat: a 31.4-N force directed 12.0° north of east (due to an auxiliary engine), a 20.7-N force...
*September 14, 2012 by marissa*

**physics**

A collision occurs between two pucks on an air-hockey table. Puck A has a mass of 0.020 kg and is moving along the x axis with a velocity of +5.5 m/s. It makes a collision with puck B, which has a mass of 0.040 kg and is initially at rest. The collision is not head-on. After ...
*January 13, 2013 by Miranda*

**Physics**

In order to convert a tough split in bowling, it is necessary to strike the pin a glancing blow as shown in Fig. 9-47. The bowling ball, initially traveling at 13.0 m/s, has four times the mass of a pin and the pin flies off at 80° from the original direction of the ball. ...
*March 5, 2014 by Anonymous*

**physics**

A 800·kg elevator is attached to a cable whose tension is 7800·N. Which of the following statements could describe the motion of the elevator? Choose all that apply. slowing down as it moves upward moving upward at constant speed speeding up as it moves downward slowing down ...
*January 17, 2013 by wally*

**Physics HELP!**

A war-wolf, or trebuchet, is a device used during the Middle Ages to throw rocks at castles and now sometimes used to fling pumpkins and pianos. A simple trebuchet is shown in the figure. Model it as a stiff rod of negligible mass 3.00 m long and joining particles of mass 74....
*November 6, 2012 by Holly*

**Math**

For one pony, thecritical force was 1.16 times its body weight. It experienced a force of 0.75 times its body weight at a speed of 2 meters per second, and a force of 0.93 times its body weight at 3 meters per second. At what speed did the pony switch from a trot to a gallop? ...
*January 26, 2012 by Aryan*

**ap chem0 frequency**

how do u do this type of problem... What is the frequency of a photon with a wavelength of 2.25 102 nm? (The speed of light in a vacuum is 2.998 108 m/s. Planck's constant is 6.626 10-34 Js c = fw. c is speed of light which you have, f is frequency for which you must solve, w ...
*September 28, 2006 by ash*

**PHYSICS--SHM**

PLZ HELP. THANKS. The balance wheel of a watch oscillates with an angular amplitude of rad and a period of 0.220 s. a) Find the maximum angular speed of the wheel. (b) Find the angular speed of the wheel when its displacement is /4 rad. (c) Find the magnitude of the angular ...
*January 27, 2007 by wooh*

**College Physics**

Two shuffleboard disks of equal mass, one orange and the other yellow, are involved in a glancing collision. The yellow disk is initially at rest and is struck by the orange disk moving with a speed vi. After the collision, the orange disk moves along a direction that makes an...
*May 18, 2011 by Josh*

**physics**

1. the pilot of a private plane flies 20km in a direction 60 degrees north of east,then 30km straight east,then 10km straight north.how far and in what direction is the plane from the starting point. 2. two forces acts on a point object as follows 100N at 170 degrees and 100N ...
*October 30, 2011 by oluwatoyin*

**physics**

1. the pilot of a private plane flies 20km in a direction 60 degrees north of east,then 30km straight east,then 10km straight north.how far and in what direction is the plane from the starting point. 2. two forces acts on a point object as follows 100N at 170 degrees and 100N ...
*October 30, 2011 by oluwatoyin*

**physics**

1. the pilot of a private plane flies 20km in a direction 60 degrees north of east,then 30km straight east,then 10km straight north.how far and in what direction is the plane from the starting point. 2. two forces acts on a point object as follows 100N at 170 degrees and 100N ...
*October 30, 2011 by oluwatoyin*

**physics**

an ice skater spins about a vertical axis at an angular speed of 15 rad/s when her arms are outstreched . she then quickly pulls her arms into her sides in a very small time interval so that the frictional force due to ice are negligible.her initial moment of inertia about the...
*February 11, 2012 by ashely*

**Physics**

A 15.0-kg block rests on a horizontal table and is attached to one end of a massless, horizontal spring. By pulling horizontally on the other end of the spring, someone causes the block to accelerate uniformly and reach a speed of 5.00 m/s in 0.460 s. In the process, the ...
*November 29, 2012 by Elizabeth*

**Physics**

A 15.0-kg block rests on a horizontal table and is attached to one end of a massless, horizontal spring. By pulling horizontally on the other end of the spring, someone causes the block to accelerate uniformly and reach a speed of 5.00 m/s in 0.460 s. In the process, the ...
*November 30, 2012 by Elizabeth*

**Physics***

A car is designed to get its energy from a rotating flywheel (solid disk) with a radius of 1.00 m and a mass of 575 kg. Before a trip, the flywheel is attached to an electric motor, which brings the flywheel's rotational speed up to 5,000 rev/min. (a) Find the kinetic energy ...
*October 20, 2011 by Allie*

**Physics**

A mass of 0.475 kg, on a frictionless table, is attached to a string which passes through a hole in the table. The hole is at the center of a horizontal circle in which the mass moves with constant speed. The radius of the circle is 0.510 m and the speed of the mass is 13.0 m/...
*April 18, 2013 by CPhy*

**Physics **

A rescue plane wants to drop supplies to isolated mountain climbers on a rocky ridge H = 231 m below. If the plane is traveling horizontally with a speed of 227 km/h (63.1 m/s), how far in advance of the recipients (horizontal distance) must the goods be dropped? 433m Suppose...
*February 7, 2012 by Kim*

**Intro-Physics Help Please**

A spaceship lands on a new planet. the crew decides to measure the speed of sound in the planets atmosphere. taking a tube with a length of 50 cm, they find that one resonant frequency occurs at 2,520 Hz, and the next resonant frequency at 2,940 hz. what is the speed of the ...
*December 7, 2014 by Kayla*

**physics**

A 2kg. lump of clay traveling at a speed of 20m/s collides with and sticks to a 5kg. lump of clay initially at rest and hanging from a string. Find the final speed of the new lump of clay. How high will the clay swing after the collision? (initial) m1=2kg. v1=20m/s (final) m2=...
*November 18, 2010 by please just check my work*

**Algebra 1**

It takes a lot of snow ofr the federal government in Washington D.C. to shut down, but even they experienced a two-hour delay last Friday. This is to allow people to take it slow in thier way to work. A commute to work that usually takes someone 24 minutes traveling at an ...
*February 7, 2008 by Libby*

**physics **

You are hired as ballistics expert and need to measure the muzzle speed of the bullet (with a mass, m = 20 g) for the gun. You fire a ballistic gun horizontally into a 2-kg ballistic pendulum (M = 2 kg) hanging at rest on a massless rod. After the bullet hits it and becomes ...
*February 23, 2011 by Anonymous*

**Physics**

A 325-kg boat is sailing 15.0° north of east at a speed of 2.00 m/s. Thirty seconds later, it is sailing 35.0° north of east at a speed of 4.00 m/s. During this time, three forces act on the boat: a 31.0-N force directed 15.0° north of east (due to an auxiliary engine), a 23.0...
*November 13, 2009 by Litany*

**Physics**

A 325-kg boat is sailing 15.0° north of east at a speed of 2.00 m/s. Thirty seconds later, it is sailing 35.0° north of east at a speed of 4.00 m/s. During this time, three forces act on the boat: a 31.0-N force directed 15.0° north of east (due to an auxiliary engine), a 23.0...
*November 13, 2009 by Litany*

**Physics**

A 358-kg boat is sailing 15.9° north of east at a speed of 1.80 m/s. Thirty seconds later, it is sailing 36.6° north of east at a speed of 3.68 m/s. During this time, three forces act on the boat: a 29.7-N force directed 15.9° north of east (due to an auxiliary engine), a 23.9...
*September 22, 2011 by Jasmin*

**physics**

A 358-kg boat is sailing 15.9° north of east at a speed of 1.80 m/s. Thirty seconds later, it is sailing 36.6° north of east at a speed of 3.68 m/s. During this time, three forces act on the boat: a 29.7-N force directed 15.9° north of east (due to an auxiliary engine), a 23.9...
*September 23, 2011 by Jasmin*

**Physics**

A 343-kg boat is sailing 16.2° north of east at a speed of 1.98 m/s. Thirty seconds later, it is sailing 37.5° north of east at a speed of 3.76 m/s. During this time, three forces act on the boat: a 30.3-N force directed 16.2° north of east (due to an auxiliary engine), a 22.3...
*February 12, 2012 by Natasha*

**Physics**

The differential gear of a car axle allows the wheel on the left side of a car to rotate at a different angular speed than the wheel on the right side. A car is driving at a constant speed around a circular track on level ground, completing each lap in 19.9 s. The distance ...
*October 28, 2012 by Sam*

**Physics**

The differential gear of a car axle allows the wheel on the left side of a car to rotate at a different angular speed than the wheel on the right side. A car is driving at a constant speed around a circular track on level ground, completing each lap in 20.2 s. The distance ...
*March 9, 2014 by Emma*

**Physics**

A student stands at the edge of a cliﬀ and throws a stone horizontally over the edge with a speed of 10.6 m/s. The cliﬀ is 25 m above a ﬂat, horizontal beach. A.) How long after being released does the stone strike the beach below the cliﬀ? The ...
*November 29, 2012 by Big Poppa Smurf*

**physics**

Two banked curves have the same radius. Curve A is banked at 11.0 °, and curve B is banked at an angle of 17.4 °. A car can travel around curve A without relying on friction at a speed of 15.3 m/s. At what speed can this car travel around curve B without relying on friction?
*February 23, 2011 by heather*

**physics**

Two banked curves have the same radius. Curve A is banked at 11.0 °, and curve B is banked at an angle of 17.4 °. A car can travel around curve A without relying on friction at a speed of 15.3 m/s. At what speed can this car travel around curve B without relying on friction?
*February 23, 2011 by heather*

**Maths**

Tom was floating down the river on a raft when, 1km down, Michael took to the water in a rowing boat. Michael rowed downstream at his fastest pace. Then he turned around and rowed back, arriving at his starting point just when Tom drifted by. If Michael's rowing speed in still...
*August 19, 2008 by Maybel*

**magnetism **

In earlier learning sequences we described how a static magnetic field cannot change the speed (and therefore kinetic energy) of a free charged particle. A changing magnetic field can, and this is one way particle beams are accelerated. Consider free protons following a ...
*December 3, 2013 by manu*

**eletromagnets**

In earlier learning sequences we described how a static magnetic field cannot change the speed (and therefore kinetic energy) of a free charged particle. A changing magnetic field can, and this is one way particle beams are accelerated. Consider free protons following a ...
*December 5, 2013 by BJ*

**physics**

In earlier learning sequences we described how a static magnetic field cannot change the speed (and therefore kinetic energy) of a free charged particle. A changing magnetic field can, and this is one way particle beams are accelerated. Consider free protons following a ...
*December 5, 2013 by J.O*

**physics**

A uranium nucleus 238U may stay in one piece for billions of years, but sooner or later it decays into an a particle of mass 6.64×10−27 kg and 234Th nucleus of mass 3.88 × 10−25 kg, and the decay process itself is extremely fast(it takes about 10−20 s). ...
*January 16, 2010 by Anonymous*

**Physics**

A cheetah starting form rest can reach a maximum speed of 28m.s in 2s and it can maintain this maxium speed for 15s after this it must rest. suppose an antelope and a cheetah initially at rest are seperated by a displcament of magnitude 100m.The antelope and cheetah see each ...
*November 11, 2011 by Sivashen*

**Physics**

Velocity/instantaneous velocity question? In a demonstration a ball falls directly to the ground. Which of the following statements about this event is not correct? (Assume downward is the positive direction.) a)The average velocity during the first half of the fall is greater...
*October 7, 2012 by Lewis*

**math-calculus**

Hi i've been struggling over this question for a while. Can anybody help me with this? A body's velocity at the time t sec is v = 2t^3 - 9t^2 +12t - 5 m/sec. Find the body's speed each time the acceleration is zero. ________________________________ What i have been doing is ...
*October 1, 2007 by manny*

**Physics**

A swimmer heads directly across a river, swimming at 1.10 m/s relative to the water. She arrives at a point 60.0 m downstream from the point directly across the river, 80.0 m wide. What is the speed of the river current? What is the swimmer's speed relative to the shore? In ...
*September 6, 2012 by Sara*

**physics**

A swimmer heads directly across a river, swimming at 1.10 m/s relative to the water. She arrives at a point 52.0 m downstream from the point directly across the river, 72.0 m wide. What is the speed of the river current? What is the swimmer's speed relative to the shore? In ...
*September 11, 2012 by Ashley*

**Physics Rotaional Kinetic Energy**

A car is designed to get its energy from a rotating flywheel with a radius of 1.50 m and a mass of 600 kg. Before a trip, the flywheel is attached to an electric motor, which brings the flywheel's rotational speed up to 4000 rev/min. (a) Find the kinetic energy stored in the ...
*March 17, 2010 by Anonymous*

**PHYSICS**

When the speed booster is set up horizontally at the edge of a table (h=1.11 m) it sends a toy car of mass m=0.06kg in the projectile motion, so that it lands at horizontal distance of x1=1.36 m away from the edge of the table. When the sam car with the same speed booster are ...
*November 1, 2012 by Emily*

**Physics**

A small block on a frictionless surface has a mass of 70 g. It is attached to a massless string passing through a hole in a horizontal surface (see diagram). The block is originally rotating in a circle of radius 45 cm with angular speed 0.80 rad/s. The string is then pulled ...
*March 24, 2014 by Luke*

**8th Grade Math**

Tom was floating down the river on a raft when, 1km lower down, Michael took to the water in a rowing boat. Michael rowed downstream at his fastest pace. Then he turned around and rowed back, arriving at this starting point just as Tom drifted by. If Michael's rowing speed in ...
*September 30, 2008 by Lexi*