Home
Class 11
PHYSICS
A railroad flatcar of mass M can roll wi...

A railroad flatcar of mass `M` can roll without friction along a straight horizontal track. Initially, a man of mass 'm' is standing on the car, which is at rest. What is the velocity of the car if man runs to the left so that his speed relative to the car is `v_(rel)`.

Text Solution

Verified by Experts

Let velocity of man w.r.t. ground be `V_(m)` and the velocity attained by car be `v_(0)` in backward direction.
`V_(rel)=v_(m)-(-v_(0))` (considering left to be positive)
`v_(m)=v_(rel)-v_(0)`

Applying conservation of momentum in x-direction,
`mv_(m)+M(-v_(0))=0`
`m(v_(rel)-v_(0))-Mv_(0)=0`
`therefore" "v_(0)=(mv_(rel))/(m+M)`
Promotional Banner

Topper's Solved these Questions

  • CENTRE OF MASS & MOMENTUM CONSERVATION

    BANSAL|Exercise Solved Examples|15 Videos

  • CENTRE OF MASS & MOMENTUM CONSERVATION

    BANSAL|Exercise Practice Exercise|20 Videos

  • GRAVITATION

    BANSAL|Exercise EXERCISE -4 Section - B|6 Videos

Similar Questions

Explore conceptually related problems

a. A rail road flat car of mass M can roll without friction along a straight horizontal track . Initially, a man of mass m is standing on the car which is moving to the right with speed v_(0) . What is the change in velocity of the car if the man runs to the left so that his speed relative to the car is v_(rel) just before he jumps off at the left end? b. If there are n men each of mass m on the car, should they all run and jump off together or should they run and jump one by one in order to give a greater velocity to the car?

a. A rail road car of mass M is moving without friction on a straight horizontal track with a velocity ct. A man of mass m lands on it normally from a helicopter. What will be the new velocity of the car? ltbgt b. If now the man begins to run on it with speed um with respect to car in a direction opposite to motion of the car, what will be the new velocity of the car?

A railroad car of mass M is at rest on frictionless rails when a man of mass m strts moving on the car towards the engine. If the car recoils with a speed v backward on the rails, with what velocity is the man aproaching the engine?

A man of mass m is standing on a stationary flat car of mass M. The car can move without friction along horizontal rails. The man starts walking with velocity v relative to the car. Work done by him

A man of mass 80 kg is riding on a small cart of mass 40 kg which is rolling along a level floor at a speed 2 m/s . He is running on the cart , so that his velocity relative to the cart is 3 m/s in the direction opposite to the motion of cart . What is the speed of the centre of the mass of the system ?

A car of mass m is driven with acceleration a along a straight level road against a constant external resistive force R. When the velocity of the car V, the rate at which the engine of the car is doing work will be

A block of mass m sits at rest on a frictionless table in a rail car that is moving with speed v_(c) along a straight horizontal track (fig.) A person riding in the car pushes on the block with a net horizontal force F for a time t in the direction of the car's motion. What is the final speed of the block according to a person in the car ?

A man of mass m is standing on a plank of equal mass m resting on a smooth horizontal surface. The man starts moving on the plank with speed u relative to the plank. The speed of the man relative to the ground is

A block of mass m sits at rest on a frictionless table in a rail car that is moving with speed v_(c) along a straight horizontal track (fig.) A person riding in the car pushes on the block with a net horizontal force F for a time t in the direction of the car's motion. According to the person on the ground. The change in KE of block is