Friday

August 28, 2015
Number of results: 22,276

**Math**

Ms. Peters drove from her home to the park at an average speed of 30 miles per hour and returned home along the same route at an average speed of 40 miles per hour. If her driving time from home to the park was 20 minutes, how many minutes did it take Ms. peters to drive from ...
*February 12, 2015 by Malachi*

**Statistics **

A researcher wishes to estimate, with 95% confidence, the proportion of adults who have high-speed internet access. Her estimate must be accurate within 4% of the true proportion. A) Find the minimum sample size needed, using a prior study that found that 54% of the ...
*June 10, 2012 by Anonymous*

**Physics**

A car is approach a corner too fast and locks up the brakes at point A and holds them on for 12.5 M to point B. The car then moves from point B at a constant speed and does into the corner. At Point C because the car is still going to fast it goes out of control and leave the ...
*January 20, 2011 by Drew*

**science**

A block of mass 0.5 kg is pushed a distance x against a spring with k=450 N/m. When released the block slides along a frictionless horizontal surface to a point B, the bottom of a vertical circular track of radius R=1 meter. The track is not smooth. When the block reaches ...
*June 18, 2011 by claire*

**p**

A certain string can withstand a maximum tension of 41 N without breaking. A child ties a 0.35 kg stone to one end and, holding the other end, whirls the stone in a vertical circle of radius 0.91 m, slowly increasing the speed until the string breaks. (a) Where is the stone on...
*July 15, 2010 by Sam*

**Science Help**

1.) A rail gun uses electromagnetic energy to accelerate objects quickly over a short distance. In an experiment, a 2.00 kg projectile remains on the rails of the gun for only 2.10x10-2 s, but in that time it goes from rest to a velocity of 4.00×103 m/s. What is the average ...
*October 18, 2014 by Kenny*

**mitx 8.01x Classical Mechanics **

Mary wants to throw a can straight up into the air and then hit it with a second can. She wants the collision to occur at height h=5.0 m above the throw point. In addition, s/he knows that she needs t1=3.0 s between successive throws. Assuming that s/he throws both cans with ...
*September 10, 2013 by youlife*

**Math - 8th grade - Please help**

I don't know the formula to figure this out. Charlie and Peter are driving around a racetrack. Charlie drives at an average speed of 108 miles per hour. Peter drives at an average speed of 99 miles per hour. Peter is given a head start of 12 miles. Charlie and Peter finish at ...
*November 16, 2012 by Chris*

**physics**

A hammer taps on the end of a 3.32 m long metal bar at room temperature. A microphone at the other end of the bar picks up two pulses of sound, one that travels through the metal and one that travels through the air. The pulses are separated in time by 5.71 ms. What is the ...
*November 21, 2008 by Anonymous*

**physics**

A hammer taps on the end of a 4.02 m long metal bar at room temperature. A microphone at the other end of the bar picks up two pulses of sound, one that travels through the metal and one that travels through the air. The pulses are separated in time by 5.79 ms. What is the ...
*November 16, 2009 by Anonymous*

**Physics**

A pitcher claims he can throw a 0.157 kg baseball with as much momentum as a 1.5 g bullet moving with a speed of 1.50 multiplied by 103 m/s. (a) What must the baseball's speed be if the pitcher's claim is valid? m/s (b) Which has greater kinetic energy, the ball or the bullet...
*November 6, 2010 by matt*

**Physics**

A hammer taps on the end of a 4.20 m long metal bar at room temperature. A microphone at the other end of the bar picks up two pulses of sound, one that travels through the metal and one that travels through the air. The pulses are separated in time by 5.45 ms. What is the ...
*November 22, 2010 by Gavin*

**Physics**

Tim and Rick both can run at speed Vr and walk at speed , Vw with Vr > vw. They set off together on a journey of distance . Rick walks half of the distance and runs the other half. Tim walks half of the time and runs the other half. How long does it take Tim to cover the ...
*October 5, 2011 by Sara*

**physics**

Search: On a pleasure cruise a boat is traveling relative to the water at a speed of 5.4 m/s due south. Relative to the boat, a passenger walks toward the back of the boat at a speed of 1.4 m/s. (a) What is the magnitude and direction of the passenger's velocity relative to ...
*January 31, 2013 by Dee*

**physics**

Estimate the speed of the parachutist descending at the constant velocity with open parachute. Assume the area of the parachute, A = 30 m^2, mass of a person, m = 100 kg, and density of air, roh = 1 kg/m^3. Enter the answer limited to the second decimal place. Hint 1: air ...
*February 21, 2011 by Anonymous*

**Math**

1. A door has a lock with a 5-digit keypad. To unlock the door, a person must enter a passcode consisting of three different digits, with each digit entered in the correct order. What is the probability that a randomly chosen passcode consisting of three different digits ...
*March 22, 2015 by Linda*

**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 600 kg. Before a trip, the flywheel is attached to an electric motor, which brings the flywheel's rotational speed up to 4,000 rev/min. (a) Find the kinetic energy ...
*November 30, 2012 by monic*

**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 600 kg. Before a trip, the flywheel is attached to an electric motor, which brings the flywheel's rotational speed up to 4,000 rev/min. (a) Find the kinetic energy ...
*December 2, 2012 by heather*

**physics**

A disk, with a radius of 0.25 m, is to be rotated like a merry-go-round through 800 rad, starting from rest, gaining angular speed at the constant rate α1 through the first 400 rad and then losing angular speed at the constant rate -α1 until it is again at rest. The ...
*December 5, 2010 by Meghan*

**physics**

(from Arons) Cars A and B travel along the same straight track. Car A is located at position s= 0.20 m at clock reading t= 0.0 s, and it maintains a constant speed of v= 0.17 m/s. Car B is located at position s=0.0 m at clock reading t= 0.04 s, and it maintains a constant ...
*October 8, 2012 by veronics*

**physics**

Along a straight road through town, there are three speed-limit signs. They occur in the following order: 56 , 33 , and 24 mi/h, with the 33 -mi/h sign located midway between the other two. Obeying these speed limits, the smallest possible time tA that a driver can spend on ...
*September 8, 2012 by andy*

**Physics**

Along a straight road through town, there are three speed-limit signs. They occur in the following order: 51 , 33 , and 26 mi/h, with the 33 -mi/h sign located midway between the other two. Obeying these speed limits, the smallest possible time tA that a driver can spend on ...
*September 12, 2013 by Briana*

**Physics**

Along a straight road through town, there are three speed-limit signs. They occur in the following order: 51 , 33 , and 26 mi/h, with the 33 -mi/h sign located midway between the other two. Obeying these speed limits, the smallest possible time tA that a driver can spend on ...
*September 12, 2013 by Briana*

**Physics**

A high-speed test track for cars has a curved section — an arc of a circle of radius R = 3000 m. The curved section is banked at angle θ = 7 . 94 ◦ from the horizontal to help the cars to stay in the road while moving at high speeds. The acceleration of gravity is 9...
*November 7, 2013 by Jakoby*

**physics**

A passenger on a moving train tosses a coin with an initial velocity of (-2.25 m/s)x unit vector + 4.26 m/s)y unit vector (from the point of view of the passenger). The train's velocity relative to the ground is (11.5 m/s)x unit vector. (a) What is the minimum speed of the ...
*September 16, 2012 by grace*

**physics**

1. Calculate the frequency (Hz) and energy (eV) of green photons with wavelength of 555nm. Photon energy = hν, where ν = frequency in Hz and h = 6.626x10-34 joule-sec, the Planck’s constant. Keep in mind that: wavelengthxfrequency = speed. 2. Andy Ruddick can serve ...
*March 1, 2009 by JeFF*

**Physics**

1) A fish jumps out of the water with a speed of 6.36 m/s. If the fish is in a stream with water speed = to 1.5 m/s, how high can the fish jump if it leaves the water traveling vertically upwards relative to the earth? 2)A ball is thrown by someone on a train moving at 10 m/s ...
*September 9, 2008 by Anne*

**Physics**

An airplane has a velocity of 454 km/h relative to the moving air. At the same time, a wind blows northward with a speed of 99 km/h relative to earth. The airplane is moving in an easterly direction relative to earth. Find the speed of the airplane to relative to earth. So, i ...
*October 1, 2010 by Jon*

**physics**

A 200-m-wide river flows due east at a uniform speed of 4.9 m/s. A boat with a speed of 9.0 m/s relative to the water leaves the south bank pointed in a direction 33o west of north. What is the (a) magnitude and (b) direction of the boat's velocity relative to the ground? Give...
*January 26, 2011 by jr*

**Physics**

James and Steve have a contest to see who can kick a football further. James kicks the football at an angle up of 57 degrees, and a speed of 75m/s. Steve kicks the ball with a speed of 100m/s, at an angle up of 48 degrees? Who wins the contest? Please show what each variable ...
*June 21, 2011 by Molly*

**school of engineering**

police officer in a patrol car parked in a70km/h observes a passing auto mobile travelling at a slow constant speed believing that of the automobile might be intoxicated the officer starts his car accelerate uniformly to 9km/h in 8s.and maintaining a constant velocity of 90km/...
*October 17, 2013 by khabat*

**algebraic reasoning**

the relationship b/w the distance d, in feet, required to stop a vehicle and s, the speed in miles per hour that the vehicle was traveling, is given by the equation d=0.0155s(squared)/f f represents the coefficient of friction b/w the tires and the road *it took a car 205 feet...
*February 23, 2008 by megan*

**physics**

On a pleasure cruise a boat is traveling relative to the water at a speed of 4.8 m/s due south. Relative to the boat, a passenger walks toward the back of the boat at a speed of 1.3 m/s. (a) What is the magnitude and direction of the passenger's velocity relative to the water...
*September 18, 2012 by manny*

**physics**

A downhill skier crosses the finishing line at a speed of 30 1 ms − and immediately starts to decelerate at 10 m s − 2 . There is a barrier 50 metres beyond the finishing line. (a) Find an expression for the skier’s speed when she is V metres beyond the finishing ...
*July 24, 2014 by Triana*

**physics**

A 11.6 kg weather rocket generates a thrust of 215.0 N. The rocket, pointing upward, is clamped to the top of a vertical spring. The bottom of the spring, whose spring constant is 399.0 N/m, is anchored to the ground. Initially, before the engine is ignited, the rocket sits at...
*November 1, 2009 by Anonymous*

**phy**

A blue ball is thrown upward with an initial speed of 20.6 m/s, from a height of 0.8 meters above the ground. 2.5 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 8.2 m/s from a height of 23.7 meters above the ground. The force of ...
*September 13, 2011 by a*

**physics**

The power needed to accelerate a projectile from rest to its launch speed v in a time t is 48.0 W. How much power is needed to accelerate the same projectile from rest to a launch speed of 2v in a time of 1/2t
*October 10, 2011 by Acceleration*

**physics**

You are walking along Main street one afternoon. At 1 PM you are 50 meters east of the intersection of Main and Elm streets. You walk due east for 30 seconds, ending up 80 meters east of the intersection of Main and Elm. You then make a left turn and walk due north for 30 ...
*August 25, 2013 by Anonymous*

**math**

andys average driving speed for a 4-hour trip was 45 miles per hour. during the first 3 hours he drove 40 miles per hour. what was his average speed for the last hour of his trip? The trip length was 4 x 45 = 180 miles. He went 3x40 = 120 the first three hours. How many miles ...
*April 28, 2007 by anonymous*

**physic**

A student on a piano stool rotates freely with an angular speed of 3.07 rev/s. The student holds a 1.38 kg mass in each outstretched arm, 0.759 m from the axis of rotation. The combined moment of inertia of the student and the stool, ignoring the two masses, is 4.72 kg·m2, a ...
*March 25, 2010 by Mary*

**physics**

a jet pilot takes his aircraft in a vertical loop. a) if the jet is moving at a speed of 2000 km/h at the lowest point of the loop, determine the minimum radius of the circle so that the centripetal acceleration at the lowest point does not exceed 6.0g's b) calculate also the ...
*October 4, 2009 by jeffery*

**physics**

A cork gun contains a spring whose spring constant is 11.0 N/m. The spring is compressed by a distance DX = 9.8 cm and used to propel a cork of mass 6.60 g from the gun. Assuming the cork is released when the spring passes through its equilibrium position (Xeq), what is the ...
*December 10, 2011 by leav*

**PHYSICS**

A mass on a frictinless inclined ramp is connected to a rope with tension T. Complete the senteces with correct selection: -increases -decreases -stays the same a) If the block is moving up the ramp and theta=30 deg, its speed initally _________ if T=(mg)/2 b) If the block is ...
*September 30, 2007 by Lily*

**Physics**

A 59-kg housepainter stands on a 16-kg aluminum platform. The platform is attached to a rope that passes through an overhead pulley, which allows the painter to raise herself and the platform. (Ignore the mass of the pulley and any friction in the pulley.) (a) With what force ...
*October 4, 2012 by Madi*

**Physics (verification)**

I would love for someone to please verify my solution for this problem: A former amusement park attraction consisted of a huge vertical cylinder rotating rapidly around its axis. The rotation speed should be sufficient for the people found inside to be stuck to the wall when ...
*December 9, 2011 by Greg*

**Physics (verification)2**

I would love for someone to please verify my solution for this problem: A former amusement park attraction consisted of a huge vertical cylinder rotating rapidly around its axis. The rotation speed should be sufficient for the people found inside to be stuck to the wall when ...
*December 10, 2011 by Greg*

**Physics**

A 10.2 kg weather rocket generates a thrust of 200N. The rocket, pointing upward, is clamped to the top of a vertical spring. The bottom of the spring, whose spring constant is 500N/m, is anchored to the ground. a) Initially before the engine is ignited, the rocket sits at ...
*November 25, 2010 by Alexandra*

**Physics**

A 930 kg sports car collides into the rear end of a 2500 kg SUV stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 2.6 m before stopping. The police officer, knowing that the coefficient of kinetic friction between tires and road is...
*October 24, 2010 by Eden*

**Physics**

Suppose that high-speed stroboscopic photographs show that the 200-g head of a golf club travels at 51 m/s just before it strikes a 50-g golf ball initially at rest on a tee. If the club head slows to at 36 m/s (in the same direction) after the collision, what is the speed of ...
*November 21, 2010 by help!*

**Physics**

Suppose that high-speed stroboscopic photographs show that the 200-g head of a golf club travels at 51 m/s just before it strikes a 50-g golf ball initially at rest on a tee. If the club head slows to at 36 m/s (in the same direction) after the collision, what is the speed of ...
*November 21, 2010 by help!*

**Physics**

Water flowing through a garden hose of diameter 2.77 cm fills a 25.0-L bucket in 1.40 min. (a) What is the speed of the water leaving the end of the hose? Answer in m/s (b) A nozzle is now attached to the end of the hose. If the nozzle diameter is one-third the diameter of the...
*March 30, 2014 by Renee*

**Physics**

Water flowing through a garden hose of diameter 2.77 cm fills a 25.0-L bucket in 1.40 min. (a) What is the speed of the water leaving the end of the hose? Answer in m/s (b) A nozzle is now attached to the end of the hose. If the nozzle diameter is one-third the diameter of the...
*March 30, 2014 by Renee*

**Physic**

Water flowing through a garden hose of diameter 2.77 cm fills a 25.0-L bucket in 1.40 min. (a) What is the speed of the water leaving the end of the hose? Answer in m/s (b) A nozzle is now attached to the end of the hose. If the nozzle diameter is one-third the diameter of the...
*March 30, 2014 by Renee*

**Physics**

A pipe that is open at both ends has a fundamental frequency of 330 Hz when the speed of sound in air is 333 m/s. What is the length of this pipe? Answer in units of cm. What is the second harmonic? What is the third harmonic? Answer in units of Hz. What is the fundamental ...
*October 1, 2012 by AJ*

**Physics**

A motorist drives for 150 km from City A to City B in 2.5 hr. He makes the return trip in 2.0 hr. Find (a) the average speed for each half of the trip, (b) the average velocity for each half of the trip, (c) the average speed of the entire trip, and (d) the average velocity ...
*June 16, 2014 by Piper*

**physics**

Cars A and B are racing each other along a straight path in following manner: Car A has head start and is a distance dA beyond starting line at t=0. The starting line is at x=o. Car A travels at constant speed vA. Car B starts at starting line but has better engine than car A ...
*September 27, 2009 by help*

**physics**

Cars A and B are racing each other along a straight path in following manner: Car A has head start and is a distance dA beyond starting line at t=0. The starting line is at x=o. Car A travels at constant speed vA. Car B starts at starting line but has better engine than car A ...
*September 27, 2009 by help*

**physics conservation of momentum**

A 0.5 kg ball is thrown horizontally towards a wall with a speed of 10 m/s. The initial velocity is chosen to be the positive x-direction for this question. The ball horizontally rebounds back from the wall with a speed of 10 m/s in the negative x-direction. What is momentum ...
*November 8, 2008 by rachel*

**Physics**

A 0.40-kg ball, attached to the end of a horizontal cord, is rotated in a circle of radius 1.3 m on a frictionless surface. If the cord will break when the tension in it exceeds 60 N, what is the maximum speed the ball can have? How would your answer be affected if there were ...
*December 24, 2010 by Matt*

**physics**

Question 4 A 0.9 kg block attached to a spring of force constant 2.1 N/m oscillates with an amplitude of 9 cm. A)Find the maximum speed of the block. Answer in units of m/s B)Find the speed of the block when it is 4.5 cm from the equilibrium position. Answer in units of m/s C)...
*November 29, 2012 by maura *

**Physics - Sound**

A sound wave travels in air at a frequency of 500 Hz. If part of the wave travels from air into water, does its frequency change? Does its wavelength change? Note that the speed of sound in air is about 340 m/s, whereas the speed of sound in water is about 1500 m/s.
*January 26, 2009 by Sam*

**physics**

A flywheel rotates at a constant angular acceleration. At time t = 1.38 s, it rotates with a speed of ω = 2.40 rad/s in the clockwise direction. At time t = 5.97 s, it rotates with a speed of ω = 2.40 rad/s in the counter-clockwise direction. What is its angular ...
*April 7, 2015 by winged17*

**physics**

A student stands at the edge of a cliff and throws a stone horizontally over the edge with a speed of 18m/s. The cliff is 50m above a flat horizontal beach, as shown in Figure 3.20. How long after being released does the stone strike the beach below the cliff? With what speed ...
*September 26, 2007 by Anonymous*

**Physics**

A cork gun contains a spring whose spring constant is 18.0 N/m. The spring is compressed by a distance ∆X = 6.0 cm and used to propel a cork of mass 7.66 g from the gun. Assuming the cork is released when the spring passes through its equilibrium position (Xeq), what is ...
*December 17, 2013 by Lina*

**Physics**

A cork gun contains a spring whose spring constant is 18.0 N/m. The spring is compressed by a distance ∆X = 6.0 cm and used to propel a cork of mass 7.66 g from the gun. Assuming the cork is released when the spring passes through its equilibrium position (Xeq), what is ...
*December 17, 2013 by Lina*

**physics**

water flows along a horizontal pipe of cross-sectional area 48cm^2 which has a constriction of cross-sectional area 12cm^2 at one place. If the speed of the water at the constriction is 4 m/s, calculate the speed in the wider section. The pressure in the wider section is 1.0 x...
*March 26, 2010 by Edwin*

**physics**

water flows along a horizontal pipe of cross-sectional area 48cm^2 which has a constriction of cross-sectional area 12cm^2 at one place. If the speed of the water at the constriction is 4 m/s, calculate the speed in the wider section. The pressure in the wider section is 1.0 x...
*March 26, 2010 by Edwin*

**physics**

You are on an airplane traveling 30° south of due west at 130.0 m/s with respect to the air. The air is moving with a speed 31.0 m/s with respect to the ground due north. 1) What is the speed of the plane with respect to the ground? 2) What is the heading of the plane with ...
*September 10, 2012 by ali*

**College Physics**

Although they don’t have mass, photons—traveling at the speed of light—have momentum. Space travel experts have thought of capitalizing on this fact by constructing solar sails—large sheets of material that would work by reflecting photons. Since the momentum of the photon ...
*October 13, 2013 by Kimmy*

**MITx: 8.01x Classical Mechanics**

Mary wants to throw a can straight up into the air and then hit it with a second can. She wants the collision to occur at height h=10.0 m above the throw point. In addition, she knows that she needs t1=4.0 s between successive throws. Assuming that she throws both cans with ...
*September 16, 2013 by simonsay*

**physics**

(a) How high a hill can a car coast up (engine disengaged) if friction is negligible and its initial speed is 78.0 km/h? m (b) If, in actuality, a 750 kg car with an initial speed of 78.0 km/h is observed to coast up a hill to a height 12.0 m above its starting point, how much...
*August 4, 2014 by mike*

**Physics**

A golfer tees off on level ground, giving the ball an initial speed of 46.5 m/s and an initial direction of 37.5 above the horizontal. a) how far from the golfer does the ball land? b) the next golfer in the group hits a ball with the same initial speed but at an angle above ...
*September 18, 2013 by Gabby*

**physics**

A,1.5kg,object,moves,up,the,y,axis,at,a,constant,speed.When,it,reaches,the,origin,the,force,F1=5.0N,at,37,deg,above,the,+x,axis,F2,=2.5N,in,the,+x,direction,F3=,3,5N,at,45,deg,below,the,neg,x,axis,and,F4,=,1.5N,in,the,neg,y,direction,are,applied,to,it,(a)Will,the,object,...
*January 19, 2008 by melissa*

**physics**

Gayle runs at a speed of 8.00 m/s and dives on a sled, initially at rest on the top of a frictionless, snow-covered hill, that has a vertical drop of 14.0 m. After she has descended a vertical distance of 5.00 m, her brother, who is initially at rest, hops on her back, and ...
*October 21, 2012 by Anonymous*

**science**

The speed of a bullet as it travels down the barrel of a rifle toward the opening is given by v = (-4.25 10^7) t^2 + (3.45 10^5) 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*

**Centrifulag pump curve**

Q4 The system on site is a pressure sand filter, with a service curve. The filter is backwashed using the feed pump, at a higher flow rate, shown as backwash curve. Service duty point : 3 m3/h Backwash duty point : 9 m3/h Part (a) (4 marks) What is the speed of the pump to ...
*January 29, 2014 by Tony*

**Physics**

A car is doing a loop-the-loop. The loop has a radius of .4m. Assume the car is starting with the minimum speed it needs in order to stay in contact with the track at all times (at the top of the track, the car is not applying a force to the track). neglect friction. What is ...
*March 6, 2012 by Melissa*

**Math**

If it takes 6 minutes to travel from point A to point B at a constant speed of 60 miles per hour, how many minutes does it take to travel the same route from point A to point B at a constant speed of 50 miles per hour?
*July 11, 2012 by Samantha*

**Math**

If 60 miles per hour is equivalent to a speed of 88 feet per second, express a speed of 45 miles per hour in feet per second. feet/sec
*May 18, 2008 by Mike*

**physics**

A 0.59 kg rubber ball has a speed of 1.50 m/s at point A and kinetic energy of 7.0 J at point B. (a) Determine the ball's kinetic energy at A Correct: Your answer is correct. J (b) Determine the ball's speed at B
*December 3, 2014 by kelly*

**physics**

hi,need help please.thank. A car is designed to get its energy from a rotating flywheel (solid disk) with a radius of 2.00 m and a mass of 525 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...
*November 22, 2009 by Chan*

**physics**

In outer space two identical space modules are joined together by a 500.0 massless cable. These modules are rotating about their center of mass. In each module, the cable is connected to a motor,so that the modules can pull each other together. The initial tangential speed of ...
*June 2, 2011 by Samantha*

**phys2**

A 60-kg astronaut is in space, far from any objects that would exert a significant gravitational force on him. He would like to move toward his spaceship, but his jet pack is not functioning. He throws a 720-g socket wrench with a velocity of 5 m/s in a direction away from the...
*March 17, 2012 by opp*

**nova**

7) You throw a 12-N stone vertically into the air from ground level. You observe that when it is 15.0 m above the ground, it is traveling at 25.0 m/s upward. Use the work –energy theorem to find (a) the stone’s speed just as it left the ground and (b) its maximum height. 8) A ...
*September 20, 2014 by papy*

**Physics**

A small block on a frictionless horizontal surface has a mass of 2.50×10−2 Kg. It is attached to a massless cord passing through a hole in the surface. The block is originally revolving at a distance of 0.300 m from the hole with an angular speed of 1.75 rad/s. The cord ...
*November 7, 2007 by Christina*

**Physics**

A missile launcher, mass M, at rest on a horizontal track fires a missile, mass m, horizontally. a) If the launch speed of the missile is v o , what (effective) coefficient of (kinetic) friction is required in order to stop the launcher within x meters? (b) Missile launcher ...
*August 8, 2012 by Chad*

**Physics**

A missile launcher, mass M, at rest on a horizontal track fires a missile, mass m, horizontally. a) If the launch speed of the missile is v o , what (effective) coefficient of (kinetic) friction is required in order to stop the launcher within x meters? (b) Missile launcher ...
*August 7, 2012 by Chad*

**mechanics**

Q3. A skeet (a small disc) of massM is fired at an angle to the horizontal with a speed v0. When it reaches the maximum height it is hit from below by a pellet of mass m (m < M) traveling vertically upward at a speed of v. The pellet is embedded in the skeet. (a) What is ...
*December 9, 2010 by sana*

**physics waves transverse longitudinal**

i real stuck on this and i really want explanations please. in which sprind do transverse waves travel faster, small diameter spring or slinky? i think this be the transverse waves but i not know how to explain why. in which spring do longitudinal waves travel faster? i think ...
*January 9, 2012 by Shreya*

**Physics (Algebra-based)**

A block starts at rest and slides down a frictionless track except for a small rough area on a horizontal section of the track.It leaves the track horizontally, flies through the air, and subsequently strikes the ground. gravity= 9.81 m/s^2. height1=4.1m---- is initially ...
*April 6, 2013 by Becky*

**Health**

Justine would like to improve her speed while dribbling the soccer ball from the defensive to the offensive side of the field. Justine can develop her speed for this type of activity by practicing · moving the ball close to her foot with control from one end of the field to ...
*December 31, 2013 by Steve*

**Physics**

Under what conditions can a quadratic function be a perfect square? Also.. A stone is thrown vertically upward at a speed of 40m/s. How long does it take to reach a height of 90m? I ended up with a quadratic of t^2-8t+18 which cannot be factored...So is the answer that the ...
*February 19, 2008 by Anonymous*

**Physics**

Under what conditions can a quadratic function be a perfect square? Also.. A stone is thrown vertically upward at a speed of 40m/s. How long does it take to reach a height of 90m? I ended up with a quadratic of t^2-8t+18 which cannot be factored...So is the answer that the ...
*February 19, 2008 by Anonymous*

**physics**

A child in danger of drowning in a river is being carried downstream by a current that has a speed of 2.10 km/h. The child is 0.600 km from shore and 0.800 km upstream of a boat landing when a rescue boat sets out. (a) If the boat proceeds at its maximum speed of 19.0 km/h ...
*October 28, 2012 by anusha*

**physics**

A mass m = 11.0 kg rests on a frictionless table and accelerated by a spring with spring constant k = 4979.0 N/m. The floor is frictionless except for a rough patch. For this rough path, the coefficient of friction is μk = 0.46. The mass leaves the spring at a speed v = 2...
*September 28, 2012 by hater of physics*

**Algebra I**

1. A Passenger train's speed is 60mi/h and a freight train's speed is 40mi/h. The passenger train travels the same distance in 1.5 h less time than the freight train. How long does each train take to make the trip? 2. Lois rode her bike to visit a friend. She traveled at 10 mi...
*October 9, 2007 by Wilford*

**Algebra 2**

how would you solve: the current in the river flowed at 3 mph. The boat could travel 24 mph downstream in half the time it took to travel 12 mi upstream. what was the speed of the boat in still water? please help. The time required to go any distance upstream a distance L is L...
*June 18, 2006 by Jonathan*

**Chem**

For a photon with = 730 nm, determine its speed, frequency, energy, and color. For frequency the formula would be v=c/lambda 3.00x10^8/7.30x10^-7=2.19x10^14/s Speed c=(v)(lambda) C=(v)(lambda) C= (2.19x10^14/s)(1.37x10^-6)=3.00x10^8 I got the wavelength by doing the ...
*October 25, 2014 by Feather*

**physics**

(Requires calculus) Prove the relativistic work-energy theorem in one dimension. The force exerted on a particle is given not by F=ma, but F=dp/dt. Using the expression for the relativistic momentum of a particle p=γmv, integrate the force exerted on the particle over the...
*September 26, 2009 by kkke*

**Physics**

1.You are stuck on a cliff and want to know how far to the bottom. You drop a rock and time how long it takes to hit the ground. If the rock takes 10 seconds to hit the ground how high is the cliff? How fast was the rock going to impact? 2. You throw a plate off your roof with...
*March 22, 2012 by Anonymous*