RE: PHYSICS

posted by .

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at 40.00 m/s relative to the flatcar. What is the resulting increase in the speed of the flatcar?

* Physics - bobpursley, Sunday, February 25, 2007 at 5:25pm

Use conservation of momentum. I will be happy to critique your thinking.

* Re: Physics - COFFEE, Sunday, February 25, 2007 at 11:19pm

Ok, so I use mv = m1v1 + m2v2??? And I would get m1 and m2 by dividing the weights by 9.8 m/s^2? Please explain.

The original momentum is..
(915+2805)g18
That is equal to the final momentum
915g*(-40+18) + 2805g(V+18)
solve for V.

• RE: PHYSICS -

0.95

Similar Questions

1. Physics

A railroad flatcar of weight W can roll without friction along astraight horizontal track. Initially, a man of weight w is standing on the car, which is moving to the right with speed v_0. What is the change in velocity of the car …
2. Physics

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at …
3. Re: PHYSICS

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at …
4. PHYSICS, still cant get it

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at …
5. Physics

A railroad flatcar is traveling at the speed of 13.0 m/s relative to an observer standing on the ground. Someone is riding a motor scooter on the flatcar. What is the velocity(magnitude and direction)of the motor scooter relative to …
6. Physics

A railroad flatcar is traveling at the speed of 13.0 m/s relative to an observer standing on the ground. Someone is riding a motor scooter on the flatcar. What is the velocity(magnitude and direction)of the motor scooter relative to …
7. physics

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2720 N) as it rolls at 18.5 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at …
8. physics

An object is shot from the back of a railroad flatcar moving at 40 km/h on a straight horizontal road. The launcher is aimed upward, perpendicular to the bed of the flatcar. The object falls: a) in front of the flatcar b) behind the …
9. Physics

A cannon is mounted on a railway flatcar, the muzzle elevated to 31.4° and pointed in the direction of the track. The cannon fires a 1.10-metric-ton projectile at 1.10 km/s. (a) If the flatcar and cannon together have a mass of 36.0 …
10. two dimensional kinematics

A freight train is moving at a constant speed of Vt. A man standing on a flatcar throws a ball into the air and catches it as it falls. Relative to the flatcar, the initial vellocity of the ball is Vib straight up. a. What are the …

More Similar Questions