Saturday

November 28, 2015
Number of results: 63,967

**ECONOMICS**

There are two ways to protect your car from theft. The "club" makes it difficult for a car thief to take your car. Lojack makes it easier for the police to catch the car thief who has stolen it. Which of these types of protection conveys a negative externality on other car ...
*April 13, 2013 by RAJA*

**physics**

A uranium nucleus (mass 238 u), initially at rest, undergoes radioactive decay. After an alpha particle (mass 4.0 u) is emitted, the remaining nucleus is thorium (mass 234 u). If the alpha particle is moving at 0.055 the speed of light, what is the recoil speed of the thorium ...
*March 3, 2014 by jill*

**physics**

A merry go round in the park has a radius of 1.8 m and a rotational inertia of 900 kg-m^2. A child pushes the merry go round with a constant force of 80 N applied at the edge and parrallel to the edge. A frictional torque of 12 Nm acts at the axle of the merry go round. What ...
*November 18, 2009 by Mare*

**physics**

A couple of astronauts agree to rendezvous in space after hours. Their plan is to let gravity bring them together. She has a mass of 66.0 kg and he a mass of 72.0 kg, and they start from rest 25.0 m apart. 1)Find his initial acceleration. 2)Find her initial acceleration. 3)If ...
*February 15, 2012 by HH*

**Calculus**

Snow is falling vertically at a constant rate of 8.0 m/s. At what angle from the vertical do the snowflakes appear to be falling as viewed by the driver of a car traveling on a straight, level road with a speed of 50k.h?
*September 26, 2013 by Robin*

**vector and mass**

A particle of mass m kg is acted on by two forces F1 and F2 with magnitudes 3root5 newtons and root5 newtons ad drections parallel to the vectors i+2j and i-2j respectively The particle is initially at a position given by vector 2i+j iv calculated the cartesian components of ...
*July 15, 2006 by rav*

**Physics**

A motorcycle officer hidden at an intersection observes a car driven by an oblivious driver who ignores a stop sign and continues through the intersection at constant speed. The police officer takes off in pursuit 1.70 s after the car has passed the stop sign. She accelerates ...
*September 3, 2015 by Izzy*

**Science**

Two Cars A car leaves San Francisco, traveling east at 65 miles per hour. The driver takes a bathroom break of 15 min every 3 hours. Another car departs New York City at the same time, traveling at 60 miles per hour. This driver takes a bathroom break of only 10 minutes every ...
*June 21, 2007 by Daniell*

**physics**

A 35-kg skier skis directly down a frictionless slope angled at 11° to the horizontal. Assume the skier moves in the negative direction of an x axis along the slope. A wind force with component Fx acts on the skier. What is Fx (in N) if the magnitude of the skier's velocity is...
*February 8, 2007 by **chocolatekisses*

**physics**

A hot-air balloon of mass 200 kg is descending vertically with downward acceleration of magnitude 1.2 m/s2. How much mass (ballast) must be thrown out to give the balloon an upward acceleration of magnitude 1.2 m/s2 (same magnitude but opposite direction)? Assume that the ...
*March 2, 2011 by karim*

**physics**

A hot-air balloon of mass 200 kg is descending vertically with downward acceleration of magnitude 1.2 m/s2. How much mass (ballast) must be thrown out to give the balloon an upward acceleration of magnitude 1.2 m/s2 (same magnitude but opposite direction)? Assume that the ...
*March 2, 2011 by karim*

**Physics**

A 0.600-kg ball traveling 4.00 m/s to the right collides with a 1.00-kg ball traveling 5.00 m/s to the left. After the collision, the lighter ball is traveling 7.25 m/s to the left. What is the velocity of the heavier ball after the collision?
*October 7, 2014 by Jay*

**Physics**

A car travels due east with a speed of 40.0 km/h. Raindrops are falling at a constant speed vertically with respect to the Earth. The traces of the rain on the side windows of the car make an angle of 54.0° with the vertical. Find the velocity of the rain with respect to the ...
*September 29, 2015 by Aly*

**Physics**

A large grinding wheel in the shape of a solid cylinder of radius 0.330 m is free to rotate on a frictionless, vertical axle. A constant tangential force of 300 N applied to its edge causes the wheel to have an angular acceleration of 1.072 rad/s2. (a) What is the moment of ...
*December 5, 2012 by anonymous*

**Physics**

A train can deccerate at 0.4 m/s. It's traveling at 160km/hr. How far in advance should it apply brakes to come to a full stop.
*November 15, 2015 by Jas*

**physics**

A block of mass m = 3.60 kg is pushed a distance d = 2.60 m along a frictionless, horizontal table by a constant applied force of magnitude F = 11.0 N directed at an angle č = 28.0° below the horizontal as shown in the figure below.
*September 27, 2014 by Anonymous*

**Physics !!**

3)A car increases its speed from 5 m/s to 35 m/s in a distance of 75 m a)what is the acceleration of the car? b)How long did it take the car to travel the 75 m? someone PLEASE help me willyah!
*June 10, 2012 by Anonymous*

**physics**

earlier in this forum, marina asked the same question as i did. unfortunately, someone did answer, very clearly, but for some reason i remained to be a little lost. Here is the question: A car traveling 90 km/h is 100 m behind a truck traveling 75 km/h. How long will it take ...
*July 20, 2008 by ruby*

**Physics **

A 97 dodge neon locks it's brakes up and skids 15 ft before hitting a motorcyclist then continues to skid another 130 ft without throwing the rider or motorcycle out from in front of the car. The only damage to car is busted head light and bumper comes off the motorcyclist ...
*August 9, 2014 by Dave*

**Physics**

A wheel starts from rest and rotates about its axis with constant angular acceleration. After 8.7s have elapsed, it has rotated through an angle of 20 radians. What is the angular acceleration of the wheel? What is the angular velocity when the time t = 8.7 s? I got the answer...
*November 21, 2014 by Ann*

**Physics**

A wheel starts from rest and rotates about its axis with constant angular acceleration. After 8.7s have elapsed, it has rotated through an angle of 20 radians. What is the angular acceleration of the wheel? What is the angular velocity when the time t = 8.7 s? I got the answer...
*November 21, 2014 by Ann*

**Physics**

What average force is required to stop an 1700 car in 7.0 if the car is traveling at 75 ?
*September 8, 2010 by Ariel*

**Physics**

What average force is required to stop an 1700 kg car in 7.0 s if the car is traveling at 75 km/h?
*September 8, 2010 by Ariel*

**physics**

What average force is required to stop an 1300 -kg car in 9.0 s if the car is traveling at 90 km/h?
*September 21, 2010 by cindy*

**Physics**

What average force is required to stop an 1600 -kg car in 8.0 s if the car is traveling at 80 km/h?
*October 11, 2010 by Katie*

**physics**

What average force is required to stop an 1900 car in 6.0 if the car is traveling at 80 ?
*April 18, 2011 by colleen*

**Physics**

A car traveling with an initial velocity of 15.5 m/s accelerates at a constant rate of 3.0 m/s2 for a time of 3.6 seconds. (a) What is its velocity at the end of this time? A) 26.3 m/s B) 18.5 m/s C) 10.8 m/s D) 22.1 m/s E) 19.1 m/s
*July 8, 2014 by Anonymous*

**physics **

A 1,600 kg car is traveling at a speed of 12.5 m/s. What is the kinetic energy of the car?
*November 15, 2012 by austin *

**Physics**

A 650 kg car traveling 8 m/s speeds up to 15 m/s in 25 s. Find the impulse on the car.
*May 2, 2013 by Zar*

**physics**

suppose the force of 20.0 N pushes on two boxes of unknown mass. We know, however, that the acceleration of the boxes is 1.25 m/s2 and the contact force has a magnitude of 2.73 N. (a) Find the mass of box 1. (b) Find the mass of box 2. So do I subtract the contact force from ...
*October 11, 2014 by Alex*

**physics**

While curling, you push a rock for 1.70 m and release it when it has a speed of 2.40 m/s. It continues to slide at constant speed for 1.40 s and then hits a rough patch of ice. It finally comes to rest 7.20 m from where it was released. What was the curling rock's magnitude of...
*September 24, 2015 by niro*

**Physics**

A train, initially stationary, has a constant acceleration of 0.5 m/s Squared. A) what is its speed of 15 s? B) What would be the total time it would take to reach a speed of 25 m/s?
*June 14, 2011 by Ralph*

**Physics**

An object initially at rest experiences an acceleration of 1.4m/s2 for 8.0s and then travels at that constant velocity for another 6.0s . What is the object’s average velocity over the 14s interval?
*February 18, 2014 by Sherri*

**Physics**

Please help! A young girl with mass 42.5kg is sliding on a horizontal, frictionless surface with an initial momentum that is due east and that has magnitude 94.0kg * (m/s) . Starting at 0s , a net force with magnitude F=( 8.10N/s )*t and direction due west is applied to the ...
*October 15, 2014 by Pavel*

**physics**

At 1:00 p.m. a car, traveling at a constant velocity of 86 km/h toward the west, is 22 km to the west of our school. How far from the school will it be at 3:30 p.m.? Answer in units of k
*February 23, 2012 by Rachel*

**physics**

At 1:00 p.m. a car, traveling at a constant velocity of 98 km/h toward the west, is 19 km to the west of our school. How far from the school will it be at 3:30
*January 15, 2012 by Rachel*

**physics**

if a 60-kg woman is riding in a car traveling at 90 km/h is her linear momentum relitive to (a) the ground or (b)the car
*February 4, 2008 by melissa*

**Physics**

a car traveling at 13 m/s^2 for 8.00 seconds. what is the distance the car travels? show all work
*December 8, 2011 by Anonymous*

**Kinematics**

A car traveling with a velocity of 4 m/s accelerates at 3 m/s^2(squared) for 10 s. How far does the car travel in the 10s?
*June 10, 2012 by Anonymous*

**Physics**

A car is traveling at 10 m/s. By what factor does the car's kinetic energy increase if its speed is doubled to 20 m/s?
*November 27, 2012 by Joan*

**Physics**

A car is traveling at 10 m/s. By what factor does the car's kinetic energy increase if its speed is doubled to 20 m/s?
*November 28, 2012 by M*

**Physics**

A car is traveling at 10 m/s. By what factor does the car's kinetic energy increase if its speed is doubled to 20 m/s?
*November 30, 2012 by Joe*

**Physical science**

How much work is required to stop a car that is 800.0 kg car that is traveling at 20.0 m/s?
*March 10, 2013 by Kizzy*

**Physical science**

How much work is required to stop a car that is 800.0 kg car that is traveling at 20.0 m/s?
*March 10, 2013 by Kizzy*

**Physics **

A car traveling at 11m/s accelerates to 2.82m/s^2 for 13 seconds how far does the car travel?
*August 25, 2013 by Jay*

**physics**

What average force is required to stop a 920kg car in 7.7s if the car is traveling at 83km/h ?
*February 15, 2015 by Dre*

**Physics**

A linear spring of stiffness k is designed to stop the 20-Mg railroad car traveling at 8 km/h within 400mm after impact. Find the smallest value of k that will produce the desired result.
*March 17, 2014 by Ivan*

**Dynamics**

A linear spring of stiffness k is designed to stop the 20-Mg railroad car traveling at 8 km/h within 400mm after impact. Find the smallest value of k that will produce the desired result.
*March 17, 2014 by Ivan*

**math**

The problem I am trying to solve is from AQA Mechanics M1 and is as follows: An object is moving in a plane. At time t=0, it is at the origin, O, and moving with velocity u. After 2 seconds it is at A where OA = -2i - 4j. After a further 3 seconds it is at B where AB = 10i - ...
*April 9, 2013 by Maggie*

**Earth and Physical Science**

A 901 kg car is traveling north down a country road when a deer crosses in front of the car. By slamming on the breaks, the care is able to decelerate at 4.0 meters per second squared. What is the frictional force between the street and the car?
*February 7, 2011 by Caitlin*

**physics**

an electric motor represented by the 4 ohm resistor below accelerates a 20g car for 40 sec. it then collides with a perfectly inelastic collision with another car that has a mass of 10g and is traveling half the first car but in the opposite direction. what is the new velocity...
*June 9, 2013 by michael*

**science**

A car traveling about 50km/h collides head-on with something solid. The car crumples, slows down and stops. Use the law of inertia to explain why a crash dummy not restrained by a seat belt in the car slams into the steering wheel.
*July 11, 2014 by duane*

**Physics URGENT**

Object 1 (mass=6.4 kg) traveling in the +x direction at a speed of 14.01m/s undergoes an inelastic collision with Object 2 (mass=5.10kg) which is at rest. Object two flies off at a speed of 11.94m/s and an angle θ2=49.8 °. The diagram below is just a sketch and is not ...
*October 22, 2015 by Nick URGENT*

**Physics **

A horizontal force, F1 = 85 N, and a force, F2 = 18.4 N acting at an angle of θ to the horizontal, are applied to a block of mass m = 2.1 kg. The coefficient of kinetic friction between the block and the surface is μk = 0.2. The block is moving to the right. A. Solve...
*October 9, 2014 by Harry*

**PHYSICS**

Particles 1 and 2, each of mass m, are attached to the ends of a rigid massless rod of length L1 + L2, with L1 = 19 cm and L2 = 75 cm. The rod is held horizontally on the fulcrum and then released. What is the magnitude of the initial acceleration of particle 1? What is the ...
*March 24, 2007 by Calvin*

**Physics-motion**

A car accelerates uniformly from rest at a. After a certain time, its acceleration becomes -a. It continues to travel and stops finally. If the total displacement of the car is L, what is the total time of travel? The answer is (4L/a)^(1/2). But why??
*March 8, 2014 by Anonymous*

**Physics**

If a ball has a constant acceleration of 10m/s^2, how fast will the ball be rolling after 4 seconds? Would you multiply acceleration times time? So 10 x 4... or would you use the equation d=1/2gt^2?
*May 29, 2010 by LK*

**PHYSICS!!!**

A net force of 30 N is applied to a 10 kg object, which starts at rest. What is the magnitude of its momentum after 3.0 seconds? Can someone please explain this as you go through the steps? I already know the equation is p=mv and I know that mass is 10kg and I just need v...
*June 2, 2012 by Christina*

**Physics**

An ore car of mass 37000 kg starts from rest and rolls downhill on tracks from a mine. At the end of the tracks, 9.9 m lower vertically, is a horizontally situated spring with constant 3.9 × 10 5 N/m. The acceleration of gravity is 9.8 m/s 2 . Ignore friction. How much is the ...
*February 8, 2013 by Ted*

**Physics**

A race car has a mass of 714 kg. It accelerates uniformly from rest, and travels 55 m in 2.95 s. What is the acceleration of the car? And, what is the net force acting on the car?
*November 28, 2012 by Molly*

**physics**

Marks: 1 A car merges onto the highway from rest in 10 seconds. The final speed of the car is 60 mph. Estimate the acceleration of the car.
*May 18, 2013 by ben*

**physics**

An object acted on by three forces moves with constant velocity. One force acting on the object is in the positive x direction and has a positive magnitude of 6.7N; a second force has a magnitude of 4.6 N and points in the negative y direction. (1)"Find magnitude of the third ...
*October 24, 2008 by john*

**physics**

An object acted on by three forces moves with constant velocity. One force acting on the object is in the positive x direction and has a positive magnitude of 6.7N; a second force has a magnitude of 4.6 N and points in the negative y direction. (1)"Find magnitude of the third ...
*October 24, 2008 by john*

**physics**

The wheels of a midsize car exert a force of 2100 N backward on the road to accelerate the car in the forward direction. If the force of friction including air resistance is 250 N and the acceleration of the car is 1.80 m/s2, what is the mass of the car plus its occupants? 4.
*November 2, 2012 by Anonymous*

**physics**

Part 2: Complete the following math problems by using the Law of Momentum Conservation. Formulas: i. Momentum = (mass) * (velocity) ii. Impulse = (Applied force) * (time) and Impulse = Change in Momentum iii. Applied Force = (Change in Momentum) / (time) iv. For multiple ...
*March 29, 2015 by Sarah*

**physics**

What is the magnitude of the electric ﬁeld if one charge is positive and the other negative, both of magnitude 5.43 µC?
*March 3, 2011 by Anonymous*

**physics: BOB or DRWLS follow up question**

What average force is required to stop an 1100-kg car in 8.0 s if it is traveling at 95 km/h? i understand what you both did, but why can't you use the V = Vo + at equation and solve for acceleration there and use that in the EF = ma equation?
*November 21, 2007 by beckii*

**physics**

the momentum of 900kg car initially moving north at 10m/s increases by 10,800. calculate the final velocity of the car.
*December 4, 2011 by gem*

**Intro to Physical Science**

A car whose mass is 1000 kg is traveling at a constant speed of 10 m/s Neglecting any friction, how much force will the engine have to supply to keep going the same speed?
*April 18, 2011 by Anonymous*

**Intro to Physical Science**

A car whose mass is 1000 kg is traveling at a constant speed of 10 m/s Neglecting any friction, how much force will the engine have to supply to keep going the same speed?
*April 18, 2011 by Anonymous*

**College Physics**

An object initially at rest experiences an acceleration of 1.4 m/s^2 for 5.0s and then travels at that constant velocity for another 7.0s. What is the object's average velocity over the 12s interval?
*December 11, 2010 by Kelly*

**Physics**

A jet plane is cruising at 225.0m/s when suddenly the pilot turns the engines up to full throttle. After travelling 2.26km, the jet is moving with a speed of 392.0m/s. What is the jet's acceleration, assuming it to be a constant acceleration?
*September 29, 2012 by Sarah*

**Physics**

A block of mass 4 kg, which has an initial speed of 2 m/s at time t = 0, slides on a horizontal surface. Find the magnitude of the work that must be done on the block to bring it to rest. Answer in units of J. If a constant friction force of magnitude 5 Newtons is exerted on ...
*November 18, 2015 by Madi*

**DYNAMICS**

A car has an initial speed of 25m/s and a constant deceleration of 3m/s^2. Determine thewvelocity of the car when t=4s. What is the displacement of the car during the 4-s time interval? How much time is needed to stop the car?
*February 17, 2013 by HELP*

**Physics 1**

6. –/1.5 points CJ8 4.P.014. My Notes | . Question Part Points Submissions Used 1 2 –/1 –/0.5 0/7 0/1 Total –/1.5 When a parachute opens, the air exerts a large drag force on it. This upward force is initially greater than the weight of the sky diver and, thus, slows him down...
*October 3, 2012 by Donald*

**phy**

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

**Physics Help**

A constant force of 100N , directed upward, is applied to a 5.0kg toy rocket by the rocket's engine. What is the rocket's acceleration? I used the equation a= F/m to get 20 m/s2 but it was wrong and I don't know where to go from here still?
*February 15, 2014 by Eiban*

**Physics **

a car traveling westward at 20 m/s turns around and travels eastward at 5 m/s. what is the change in velocity of the car?
*October 5, 2011 by Katie*

**Physics**

A car traveling at 18 m/s accelerates at 5.5 m/s2 for 9 s. How far does the car travel during the time it is accelerating for 9 seconds?
*October 14, 2011 by Idk*

**PHYSICS - PLEASE HELP**

A car is traveling at 10 m/s. By what factor does the car's kinetic energy increase if its speed is doubled to 20 m/s?
*November 28, 2012 by Mary*

**science**

if the car had a mass of 2050 kg and was traveling 25 miles per second, what was the car momentum?
*December 20, 2012 by none ya*

**physics**

A 1,400kg car is traveling in a straight line. Its momentum is equal to 2,000 kg. What is the velocity of the car?
*January 23, 2014 by karen*

**physics**

a car traveling at 7 m/s accelerates to a velocity of 12.0 m/s in 2.0s. what is the acceleartion of the car?
*September 25, 2012 by jenna*

**physics**

A 90Kg box is pushed by a horizontal force F at constant speed up a ramp incined at 28 degrees. Determine the magnitude of applied force when teh ramp is frictionless and when the coefficient of kinetic friction is 0.18
*June 8, 2012 by Rose*

**Physics**

Mass m1 = 0.5 kg moves with constant velocity v1i = 2.5 m/s along the x-axis and collides with mass m2 = 2.6 kg, which moves with velocity v2i = 3.1 m/s, as sketched below(completely vertical). After the collision, m1 and m2 stick together. a.) Find the angle, θ, between ...
*March 24, 2015 by Emma*

**physics**

A rifle bullet with a mass of 16.5 g traveling toward the right at 285 m/s strikes a large bag of sand and penetrates it to a depth of 22.6 cm. Determine the magnitude and direction of the friction force (assumed constant) that acts on the bullet.
*June 18, 2014 by Sara*

**physics**

A car has a mass of 1.34 × 10^3 kg. If the force acting on the car is 6.46 × 10^3 N to the east, what is the car’s acceleration?
*October 20, 2011 by Stephen*

**Physics**

An object with a mass of 2.728x10^1 kg is subjected to a force of 1.31851x10^3 N directed at an angle of 1.056x10^1 degrees from the x axis. A second force of 1.93826x10^3 N acting in the negative Y directions is also applied to the object. To two significant figures what is ...
*October 22, 2010 by christine*

**College Physics **

Two forces, F⃗ 1 and F⃗ 2, act at a point, as shown in the picture. (Figure 1) F⃗ 1 has a magnitude of 8.20N and is directed at an angle of α = 55.0∘ above the negative x axis in the second quadrant. F⃗ 2 has a magnitude of 6.40N and is ...
*April 5, 2014 by Danilo*

**Physics**

A 25kg crate is sitting at the bottom of an inclined plane. The inclined plane 12m long meets the horizontal at an angle of 15 degrees and has a coefficient of friction of 0.55. A force is applied to the crate so as to slide the crate up the incline at a constant speed. What ...
*February 25, 2012 by Rob*

**math word problem**

A car is traveling on a road that is perpendicular to a railroad track. When the car is 30 meters from the crossing, the car's new collision detector warns the driver that there is a train 50 meters from the car and is heading towards the same crossing. How far is the train ...
*March 10, 2009 by Debbie*

**physical**

A car starts from rest its acceleration is 2m.s-2 in a straight line. What is it displacement after 10 seconds?
*February 4, 2011 by Zinhle*

**Physics**

a racing car has a uniform acceleration of 4 m/s2 What distance will it cover in 10secs after its start
*August 10, 2013 by Anonymous*

**Physics**

a 5kg block is pushed 3m up a vertical wall with constant speed by a constant force of magnitude f applied at an angle of 30 degrees with the horizontal. if the coefficient of kinetic friction between block and wall is .3, determine the work done by a) f b) the force of ...
*April 20, 2013 by Annette*

**physical**

You are driving along a highway at 27.7 m/s when you hear a siren. You look in the rear-view mirror and see a police car approaching you from behind with a constant speed. The frequency of the siren that you hear is 1830. Hz. Right after the police car passes you, the ...
*July 16, 2012 by itufizik*

**Physics**

A long, thin rod (length = 4.0 m) lies along the x axis, with its midpoint at the origin. In a vacuum, a +5.0 µC point charge is fixed to one end of the rod, while a -5.0 µC point charge is fixed to the other end. Everywhere in the x, y plane there is a constant external ...
*January 26, 2013 by Amy*

**Physics**

A long, thin rod (length = 4.0 m) lies along the x axis, with its midpoint at the origin. In a vacuum, a +5.0 µC point charge is fixed to one end of the rod, while a -5.0 µC point charge is fixed to the other end. Everywhere in the x, y plane there is a constant external ...
*January 26, 2013 by Amy*

**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**

Coasting due east on your bicycle at 8.0 m/s, you encounter a sandy patch of road 7.4 m across. When you leave the sandy patch your speed has been reduced to 5.5 m/s. Assuming the bicycle slows with constant acceleration, what was its acceleration in the sandy patch? Give both...
*September 16, 2013 by john*

**PHYSICS**

A 25,000 kilogram train is traveling down a track at 20 meters per second. A cow wanders onto the tracks 75 meters ahead of the train, causing the conductor to slam on the brakes. The rain skids to a stop. If the brakes can provide 62,500 Newtons of friction, will the ...
*February 26, 2012 by TRACY*