NEET2008PhysicsCenter of Mass, Momentum and CollisionActual
A particle of mass m is projected with velocity y making an angle of 45^ with the horizontal. When the particle lands on the level ground the magnitude of the change in its momentum will be
Options
- A2 m v
- Bm v / 2
- Cm v 2
- Dzero
Correct answer
C. m v 2
Step-by-step solution
Key Idea: Required momentum is the difference of final and initial momentum. The situation is shown in figure. Change in momentum, aligned p & = p _f- p _i & =m ( v _f- v _i ) & =m [ (v 45^ i -v 45^ j ) . & . - (v 45^ i +v 45^ j ) ] & =m [ ( v 2 i - v 2 j )- ( v 2 i + v 2 j ) ] & =- 2 m v j & [ p ]= 2 m v aligned Alternative : The horizontal momentum does not change. The change in vertical momentum is m v -(-m v )=2 m v 1 2 = 2 m v