Friday

October 9, 2015
Number of results: 22,681

**physics**

Heather and Jerry are standing on a bridge 53m above a river. Heather throws a rock straight down with a speed of 12m/s . Jerry, at exactly the same instant of time, throws a rock straight up with the same speed. Ignore air resistance. How much time elapses between the first ...
*October 9, 2014 by Haley*

**Math**

Please help me! I don't even know where to start :( my teacher took this question up on friday but i was sick, and we have a test tomorrow! -Car A travels from Barrie to Subuiry at an average speed of 90km/h -Car B travels from Subury to Barrie at an average speed of 80km/h -...
*March 7, 2010 by Dawn*

**physics(URGENT!!!!!)**

A spherical non-rotating planet (with no atmosphere) has mass m1= 5 ×1024 kg and radius r1= 7000 km. A projectile of mass m2≪m1 is fired from the surface of the planet at a point A with a speed vA at an angle α=30∘ with respect to the radial direction. In...
*December 8, 2013 by Anonimus*

**physics**

Two meteoroids 250,000 km from Earth are moving at 2.1 km/s. Meteor one is headed in a straight path for Earth, while meteor two is on a path that will come within 8500 km from the Earth's center. (A) What is the speed of the first meteroid when it strikes Earth. (B) What is ...
*March 17, 2009 by James*

**Physics**

Two meteoroids 250,000 km from Earth are moving at 2.1 km/s. Meteor one is headed in a straight path for Earth, while meteor two is on a path that will come within 8500 km from the Earth's center. (A) What is the speed of the first meteroid when it strikes Earth. (B) What is ...
*March 19, 2009 by James*

**Calc**

A student is in a 20 week calc class. The function f(t)=50-50e^0.2t f(t) measures the students problem speed in t weeks -how many problems per hour can a student solve at the beginning of the course - how many problems per hour can a student solve halfway through the course -...
*July 20, 2012 by Marshall*

**physics**

A siren mounted on the roof of a firehouse emits sound at a frequency of 900 Hz. A steady wind is blowing with a speed of 15 m/s. Take the speed of sound in calm air to be 343 m/s. (c) Firefighters are approaching the siren from various directions at 15.0 m/s. What frequency ...
*April 19, 2010 by Stephanie*

**physics helpppp**

particle 1 of mass m1 = 0.29 kg slides rightward along an x axis on a frictionless floor with a speed of 1.8 m/s. When it reaches x = 0, it undergoes a one-dimensional elastic collision with stationary particle 2 of mass m2 = 0.40 kg. When particle 2 then reaches a wall at xw...
*March 30, 2010 by Anonymous*

**physic**

A police officer arrives at the scene of the collision of the two snowmobiles (Figure 1) to find both drivers unconscious. When the two vehicles collided, their skis became entangled and the two snowmobiles remained locked together as they skidded to a stop. One driver was ...
*April 2, 2007 by sam*

**Physics**

A centrifuge is a common laboratory instrument that separates components of differing densities in solution. This is accomplished by spinning a sample around in a circle with a large angular speed. Suppose that after a centrifuge in a medical laboratory is turned off, it ...
*October 23, 2011 by Jc*

**advanced functions HELP!!!**

the function S(d)=93logd+65 relates the speed of the wind, S, in mile per hour, near the centre of a tornado to the distance that the tornado travels, d, in miles. a)Calculate the avg. rate of change for the speed of the wind at the centre of a tornado from mile 10 to mile 100...
*December 10, 2008 by james*

**PHYYYYYSICS 4**

A plane points its nose due north and flies at a speed of 71 m/s relative to the air. The plane enters a strong wind that blows at a speed of 23 m/s due west relative to the ground. What is the angle of the plane's trajectory according to an observer standing on the ground? ...
*September 18, 2014 by Carissa*

**physics**

A person is standing on and facing the front of a stationary skateboard while holding a construction brick. The mass of the person is 87.0 kg, the mass of the skateboard is 4.10 kg, and the mass of the brick is 2.50 kg. If the person throws the brick forward (in the direction ...
*January 15, 2015 by Daniel*

**physics (sorry about all of these!)**

A satellite moves in a stable circular orbit with speed Vo at a distance R from the center of a planet. For this satellite to move in a stable circular orbit a distance 2R from the center of the planet, the speed of the satellite must be?? I said that F=ma, but m doesn't ...
*January 20, 2008 by Hannah*

**PHYSICS**

An odometer in a car has a reading of 50 km at the beginning of a trip and a reading of 125 km half an hour later. What is the average speed of the car? A. 3.75 km/h B. 62.5 km/h C. 1250 km/h D. 250 km/h The only way to find the average speed is to divide the total distance by...
*July 21, 2010 by Anonymous*

**Physics**

A simple pendulum of length 2.00m is made with a mass of 2.00kg. The mass has speed of 3.00 m/s when the pendulum is 30 degrees above its lowest position. -What is the maximum angle away from the lowest position the pendulum will reach? -What is the speed of the mass when the ...
*November 9, 2014 by Alex*

**Physics**

A simple pendulum of length 2.00m is made with a mass of 2.00kg. The mass has speed of 3.00 m/s when the pendulum is 30 degrees above its lowest position. -What is the maximum angle away from the lowest position the pendulum will reach? -What is the speed of the mass when the ...
*November 5, 2014 by Alex*

**physics**

In order to convert a tough split in bowling, it is necessary to strike the pin a glancing blow as shown in the figure. Assume that the bowling ball, initially traveling at 15.0 m/s, has four times the mass of a pin and that the pin goes off at 75° from the original direction ...
*October 20, 2011 by kago*

**physics**

An open-topped tank completely filled with water has a release valve near its bottom. The valve is 1.63 m 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 a = 12.3 times the cross...
*October 25, 2011 by melisa*

**Mathematics**

A car travelling at an average speed of 55kph leaves Town A for Town B a distance of 120 kilometres. At the same time, another car, travelling on the same highway at an average speed of 45kph, leaves Town B for Town A. In how many leaves will they meet? How far from Town A ...
*January 18, 2015 by Kyrstal*

**Science Plz help**

1. Acceleration involves a change in ____. speed velocity displacement direction 2. Which of the following statements about acceleration is true? Like velocity, acceleration has a direction. Your acceleration is positive when you speed up. Your acceleration is negative when ...
*March 29, 2013 by Jman*

**science**

A particle had a speed of 18m/s at a certain time and 2.4 s laer its speed was 30 m/s in the opposite direction. What were the magnitude and direction of the average acceleration of the particle during the 2.4s interval? I got -5m/s^2 but the book said it was 20m/s^2 in the ...
*September 10, 2006 by Sarah*

**Physics**

Two ships in a heavy fog are blowing their horns, both of which produce sound with a frequency of 165.0 Hz One ship is at rest; the other moves on a straight line that passes through the one at rest. If people on the stationary ship hear a beat frequency of 3.5 Hz, what is the...
*November 22, 2011 by Cooper*

**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 4, 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 5, 2015 by kanga*

**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 7, 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 16, 2015 by kudu*

**Physics**

From the top of a tower is an object with mass 25 kg is lowered at constant speed, 4 m / s with a rope to the ground. After 10 seconds of the rope breaks, and the object falls freely. From the moment (the rope breaks) there are 12 seconds to those standing on top of the tower ...
*October 18, 2010 by Oddbjørn*

**physics**

A truck of mass 2000kg travelling due south collides at an intersection with a car of mass 1200kg travelling due east. The car and truck become entangled and move off to the south-east. The truck driver claims to have been travelling at exactly 60km/hr(the speed limit) just ...
*April 13, 2012 by Lycra*

**physics**

Question Part Points Submissions Used 1 2 3 4 0/0.37 0/0.37 –/0.37 –/0.37 4/15 1/15 0/15 0/15 Total 0/1.48 ...A diamond in air is illuminated with white light. On one particular facet, the angle of incidence is 46.05°. Inside the diamond, red light (ë = 660.00 nm in vacuum) ...
*May 4, 2014 by ryan*

**Physics**

Use principles of force and kinematics to answer these: a. A 40 kg skater pushes on the 60 kg skater (initially at rest). As they collide, the 40 kg skater pushes on the 60 kg skater, applying a force 100 Newtons for 1.2 seconds. Find the velocity at which each of them ends up...
*November 1, 2010 by jen*

**physics**

Use principles of force and kinematics to answer these: a. A 40 kg skater pushes on the 60 kg skater (initially at rest). As they collide, the 40 kg skater pushes on the 60 kg skater, applying a force 100 Newtons for 1.2 seconds. Find the velocity at which each of them ends up...
*November 1, 2010 by jen*

**Advanced Maths (Vectors) AQA Level, please help?**

A boat which can travel at 5m/s in still water is crossing a river 200 m wide.the rate of the flow of the river is 2 m/s assumed uniform at every point in the river. Point A and B are directly opposite to each other across the river. a) If the boat leaves A and steer towards B...
*February 12, 2012 by jat*

**physics**

Two curves on a highway have the same radii. However, one is unbanked and the other is banked at an angle θ. A car can safely travel along the unbanked curve at a maximum speed v0 under conditions when the coefficient of static friction between the tires and the road is...
*February 28, 2013 by Dee*

**Physics**

Two curves on a highway have the same radii. However, one is unbanked and the other is banked at an angle θ. A car can safely travel along the unbanked curve at a maximum speed v0 under conditions when the coefficient of static friction between the tires and the road is...
*March 4, 2013 by Dee*

**Physics**

At the instant the traffic light turns green, an automobile that has been waiting at an intersection starts ahead with a constant acceleration of 2.50 m/s^2. At the same instant, a truck, traveling with a constant speed of 15.4 m/s, overtakes and passes the automobile. How far...
*September 12, 2006 by Josh*

**physics**

As shown below, a bullet of mass m and speed v passes completely through a pendulum bob of mass M. The bullet emerges with a speed of v/2. The pendulum bob is suspended by a stiff rod of length and negligible mass. What is the minimum value of v such that the pendulum bob will...
*March 22, 2009 by jim*

**(1-15) Chemistry - Science **

Assume a gas of molecular mass M g/molecule obeys the Maxwell Boltzmann distribution of speeds at temperature T. If u2> u1, the ratio of the number of molecules at speed u2 to the number at speed u1 a) is always less than one. b) is always greater than one. c) can be either...
*May 10, 2014 by Ana *

**math**

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 the same time. How far does Charlie drive? ...
*November 16, 2012 by Chris*

**physics**

An arrow is short vertically upward with an initial speed of 25m/s. When it's exactly halfway to the top of its flight, a second arrow is launched vertically upward from the same spot. The second arrow reaches the first arrow just as the first arrow reaches its highest arrow. ...
*February 18, 2011 by Mary*

**physics**

A projectile is fired through the air. It is launched from the ground, and travels without interference from wind or air resistance, landing on a raised platform above the field. Compare the following values: 1-Initial speed vs. final speed: 2-Initial vertical velocity vs. ...
*June 23, 2013 by Din123*

**Physics**

A parachutist with mass 79.7 kg jumps from an airplane traveling at a speed vi= 112 km/hr at a height H = 2570 m. He lands with a speed of vf = 5.21 m/s. What is the change in mechanical energy (J) of the earth- parachutist system from just after the jump to just before ...
*June 18, 2011 by Casey *

**Physics**

A golfer has to hit a ball over a tree that is 12.0 meters high from 40.0 meters away. The ball is hit with speed v at an angle (-) to the horizontal. Neglect any effect due to air. The golfer hits the ball with an initial velocity 30 degrees to the horizontal. Calculate the ...
*February 7, 2013 by Emilea*

**physics**

A ballistic pendulum, as shown in the figure, was a device used in the past century to measure the speed of bullets. The pendulum consists of a large block of wood suspended from long wires. Initially, the pendulum is at rest. The bullet strikes the block horizontally and ...
*March 4, 2008 by shelby*

**Algebra**

I'm having a little trouble with this problem... Please try and walk me through the problem, too: #1. A motorboat leaves a dock and travels at an average speed of 15 mi/h toward an island. The average speed on the return trip is 10 mi/h. How far is the island from the harbor ...
*November 20, 2008 by Celina*

**Physics**

A basketball player makes a jump shot. The 0.700 kg ball is released at a height of 2.10 m above the floor with a speed of 7.30 m/s. The ball goes through the net 3.10 m above the floor at a speed of 3.10 m/s. What is the work done on the ball by air resistance, a ...
*February 23, 2007 by Mary*

**physics**

As some molten metal splashes, one droplet flies off to the east with initial speed vi at angle θi above the horizontal, and another droplet flies off to the west with the same speed at the same angle above the horizontal, as inthe figure. In terms of vi and θi, find...
*October 15, 2010 by natalie*

**phsyics**

The 3.0cm-diameter water line in the figure splits into two 1.0cm -diameter pipes. All pipes are circular and at the same elevation. At point A, the water speed is 2.0 m/s and the gauge pressure is 50 kPa. What is the gauge pressure at point B. I keep getting an answer that I ...
*November 15, 2010 by Allison*

**physics**

As some molten metal splashes, one droplet flies off to the east with initial speed vi at angle θi above the horizontal, and another droplet flies off to the west with the same speed at the same angle above the horizontal, as inthe figure. In terms of vi and θi, find...
*February 18, 2011 by Anonymous*

**college physic**

A stunt driver wants to make his car jump over 8 cars parked side by side below a horizontal ramp.(a)With what minimum speed must he drive off the horiontal ramp?The vertical height of the ramp is 1.5m above the cars and the horizontal distance must be clear is 20m.(b)If the ...
*June 23, 2011 by noah*

**college physic**

A stunt driver wants to make his car jump over 8 cars parked side by side below a horizontal ramp.(a)With what minimum speed must he drive off the horiontal ramp?The vertical height of the ramp is 1.5m above the cars and the horizontal distance must be clear is 20m.(b)If the ...
*June 23, 2011 by noah*

**College Physics**

The electron-volt, eV, is a unit of energy (1eV = 1.602 ·10–19 J, 1 MeV = 1.602 ·10–13 J). Since the unit of momentum is an energy unit divided by a velocity unit, nuclear physicists usually specify momenta of nuclei in units of MeV/c, where c is the speed of light (c = 2.998...
*October 13, 2013 by Kimmy*

**Physics(Please check)**

A car (mass = 1140 kg) is traveling at 27.3 m/s when it collides head-on with a sport utility vehicle (mass = 2380 kg) traveling in the opposite direction. In the collision, the two vehicles come to a halt. At what speed was the sport utility vehicle traveling? I did 1140(27.3...
*June 3, 2012 by Hannah*

**physics help**

An amusement park ride consists of a car moving in a vertical circle on the end of a rigid boom of negligible mass. The combined weight of the car and riders is 5.1 kN, and the circle’s radius is 10 m. At the top of the circle, what are the (a) magnitude FB and (b) direction...
*March 3, 2010 by Anonymous*

**physics**

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 mike*

**Physics**

A mouse of mass 5.0 g spots the corner of a peanut butter sandwich of mass 8.0 g left on an ice rink after a game. Excited, the mouse runs out onto the ice, but immediately begins to slide. The mouse reaches the peanut butter sandwich and sinks its teeth in. Both the mouse and...
*December 8, 2011 by Anonymous*

**physics**

An open-topped tank completely filled with water has a release valve near its bottom. The valve is h = 1.9 m 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, A_T, is 38 times the cross-...
*November 27, 2012 by Brandon*

**physics**

A ball player hits a home run, and the baseball just clears a wall 17.6 m high located 122.0 m from home plate. The ball is hit an an angle of 35° to the horizontal, and air resistance is negligible. Assume the ball is hit at a height of 1.1 m above the ground. (a) What is the...
*November 24, 2014 by JAck*

**Physics**

A bullet with a mass m=12.5 g and speed v=85.4 m/s is fired into a wooden block with M=113 g which is initially at rest on a horizontal surface. The bullet is embedded into the block. The block-bullet combination slides across the surface for a distance d before stopping due ...
*October 25, 2012 by Devin*

**physics**

While riding in a hot air balloon, which is steadily descending at a speed of 1.39 m/s, you accidentally drop your cell phone. (a) After 4.00 s, what is the speed of the cell phone? (b) How far is the cell phone below the balloon after this time? d = m (c) What are your ...
*September 14, 2014 by Anonymous*

**physics**

While riding in a hot air balloon, which is steadily descending at a speed of 1.39 m/s, you accidentally drop your cell phone. (a) After 4.00 s, what is the speed of the cell phone? (b) How far is the cell phone below the balloon after this time? d = m (c) What are your ...
*September 14, 2014 by Dann*

**8th grade math - Ms. Sue please**

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 the same time. How far does Charlie drive? ...
*November 16, 2012 by Chris*

**physics 70**

A .275 kg. object is swung in a vertical circular path on a string .850 m. long. A) What are the forces acting on the ball at any point along this path? B) Draw free-body diagrams for the ball when it is at the bottom of the circle and when it is at the top. C) If its speed is...
*April 21, 2013 by Annette*

**College Physics**

The rotor is an amusement park ride where people stand against the inside of a cylinder. Once the cylinder is spinning fast enough, the floor drops out. A-What force keeps the people from falling out the bottowm of the ride? I think that it's the Normal force? B-If the ...
*October 21, 2008 by JP*

**Physics**

Let f be the frequency, v wav the speed, and T the period of a sinusoidal traveling wave. The correct relationship is: a)f=1/T b)f=vwav + T c)f=vwavT d)f=vwav/T e)f=T/vwav My thoughts: I think the answer is D.Since frequency is equal to T=1/f so f=1/T. Vwav is connected to f ...
*February 13, 2007 by susan*

**physics**

A 0.005-kg bullet traveling horizontally with a speed of 1.00 103 m/s enters an 20.3-kg door, imbedding itself 10.6 cm from the side opposite the hinges as in the figure below. The 1.00-m-wide door is free to swing on its hinges. (c) At what angular speed does the door swing ...
*October 26, 2010 by Amy*

**Physics!**

The two stars in a certain binary star system move in circular orbits. The first star, Alpha, has an orbital speed of 36 km/s. The second star, Beta, has an orbital speed of 12 km/s. The orbital period is 137 d. a) What is the mass of the star alpha? b) What is the mass of the...
*June 3, 2011 by Allison*

**physics**

just a couple more questions 1.) The power needed to accelerate a projectile from rest to is launch speed v in a time t is 43.0 W. How much power is needed to accelerate the same projectile from rest to launch speed of 2v in a time of 1/2t? 2.)A ball is fixed to the end of a ...
*October 20, 2010 by jo*

**physics**

just a couple more questions 1.) The power needed to accelerate a projectile from rest to is launch speed v in a time t is 43.0 W. How much power is needed to accelerate the same projectile from rest to launch speed of 2v in a time of 1/2t? 2.)A ball is fixed to the end of a ...
*October 20, 2010 by jo*

**physics**

just a couple more questions 1.) The power needed to accelerate a projectile from rest to is launch speed v in a time t is 43.0 W. How much power is needed to accelerate the same projectile from rest to launch speed of 2v in a time of 1/2t? 2.)A ball is fixed to the end of a ...
*October 21, 2010 by jo*

**physics**

A 11.1-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 3.12 m/s in 1.17 s. In the process, the spring...
*November 13, 2012 by Michelle*

**physics**

A 10 kg crate is pulled up a rough incline with an initial speed of 1.5 m/s. The pulling force is 100 N parallel to the incline, which makes an angle of 20 degrees with the horizontal. If the coefficient of kinetic friction is .40 and the crate is pulled a distance of 5 m, (a...
*October 22, 2007 by Anonymous*

**physics**

A 10 kg crate is pulled up a rough incline with an initial speed of 1.5 m/s. The pulling force is 100 N parallel to the incline, which makes an angle of 20 degrees with the horizontal. If the coefficient of kinetic friction is .40 and the crate is pulled a distance of 5 m, (a...
*October 23, 2007 by Anonymous*

**Physics**

A hammer taps on the end of a 8.13m 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 10.00ms. What is the ...
*November 21, 2012 by rory*

**Physics**

You toss a tennis ball straight upward. At the moment it leaves your hand it is at a height of 1.5 m above the ground, and it is moving at a speed of 8.0 m/s. (a) How much time does it take for the tennis ball to reach its maximum height? (b) What is the maximum height above ...
*September 6, 2014 by John*

**College Math**

The posted speed limit on many U.S. highways is 65 miles per hour. What is this speed in feet per second? My answer was 5720 feet per second. The other answers that would be a possibility are: (A)3600 feet per second, (B)95 1/3 feet per second, (C) 5720 feet per second, which ...
*August 28, 2012 by Carol*

**physics**

A box and its contents have a total mass M = 9 kg. A string passes through a hole in the box, and you pull on the string with a constant force F = 77 N (this is in outer space; there are no other forces acting). (a) Initially the speed of the box was vi = 5 m/s. After the box ...
*November 16, 2011 by Anonymous*

**Physics**

A 0.490 kg hockey puck, moving east with a speed of 5.80 m/s, has a head-on collision with a 0.870 kg puck initially at rest. Assume a perfectly elastic collision. (Let east be the +x direction.) (a) What will be the speed of each object after the collision? 0.490 kg puck 0....
*October 20, 2011 by kago*

**physics help**

The drawing shows a collision between two pucks on an air-hockey table. Puck A has a mass of 0.030 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 0.055 kg and is initially at rest. The collision is not head-...
*November 5, 2010 by danny*

**physics**

two different masses have equal, non zero kinetic energies. the momentum of the smaller mass is? what is the magnitude of momentum of a 0.140 baseball traveling at 45.0m/s? a 2.00g bullet hits and becomes embedded in 5.00 kg wood block which is hanging from a 1.60m long string...
*February 25, 2009 by tina*

**physics**

two different masses have equal, non zero kinetic energies. the momentum of the smaller mass is? what is the magnitude of momentum of a 0.140 baseball traveling at 45.0m/s? a 2.00g bullet hits and becomes embedded in 5.00 kg wood block which is hanging from a 1.60m long string...
*February 25, 2009 by tina*

**physics **

A metal emits photoelectrons when yellow light is made to fall on it. Which of the following is correct when the metal is irradiated by a violet light? Choose one answer. a. The speed of electrons would increase. b. The speed of electrons would decrease. c. The number of ...
*May 1, 2011 by ashley --- HELP PLEASEE!!!*

**Physics**

A 645-kg elevator starts from rest. It moves upward for t = 3.13 s with a constant acceleration until it reaches its constant cruising speed of v = 1.26 m/s. It moved 2.75m during that time. a) What is the average power (W)is delivered by the motor during the initial ...
*December 14, 2011 by Sarah*

**physics**

A 1.20 kg mass on a horizontal spring oscillates on a frictionless surface with a displacement as a function of time given by x(t) = 0.075cos(4.16t – 2.45). (Units are standard units.) a.) Find the time for one complete vibration. b.) Find the force constant of the spring. c...
*July 31, 2012 by Lauren*

**physics**

A tube is open only at one end. A certain harmonic produced by the tube has a frequency of 445.0 Hz. The next higher harmonic has a frequency of 525.9 Hz. The speed of sound in air is 343 m/s. (a) What is the integer n that describes the harmonic whose frequency is 445.0 Hz? (...
*April 29, 2007 by Cavin*

**Physics**

(a)A car travels exactly once around a circle of radius 5.0 m at constant speed of 3.0 m/s. What is the car’s average velocity (magnitude and direction) during this interval? Explain/justify. (b)Repeat the calculation of average velocity if the car travels halfway around the ...
*September 19, 2009 by Sonya*

**physics**

A mass of 2 kg is hung from the lower end of a vertical spring and extends it by 40 cm. The mass is now pulled down a further 20 cm and is then released from rest so that it oscillates about the equilibrium position. Determine : a) the spring stiffness constant k for the ...
*April 21, 2012 by minha*

**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*