Question

a train of mass M= π kg is moving on a circular track of radius R with a constant speed V=2m/s the length of the train is half of the perimeter of the track .The linear momentum of the train will be

Answer 1

2π is answer for your questions

Answer 2

Let the whole mass be concentated at the centre of mass so we can consider a point mass at 2R/pi because cente of mass of semi circular ring . And we can considered train as semi circular ring on track

Momentum =mass×velocity

velocity = distance of particle from centre ×angular velocity

P=mv

P=mwr/2pi

P=mvr/2pir

Mass is pi sothat mass and pi cancel out as well as r

We get

P=2v

P=4