Question

Define momentum.Write its si unit.Calculate the change in movementum of a car weighing 2500kg, when its speed increses from 54kmph to 72kmph uniformly in 20 seconds

Answer 1

Momentum is a Effect of motion or Velocity...It is a vector quantity and its direction is along the direction of velocity...

P is the symbol used to denote this physical quantity...

If an object having mass m and velocity v , then it can be calculated as Product of Mass m and Velocity v...i.e, P = m x v

S.I unit of momentum

P = m x v = kg x m/s

Mass of car = 2500 kg

Initial velocity of car , u =54 kmph = 54 × 5/18
= 3 × 5 = 15 m/s
Final velocity of car , v =72 kmph = 72 × 5/18
=4 × 5 =20m/s

Initial Momentum , P1 = m x u = 2500 × 15
Final Momentum , P2= m x v = 2500 × 20

Therefore , Change in momentum
= Final momentum - Initial momentum
= p2 - p1
=2500 × 20 - 2500 × 15
= 2500 × ( 20 - 15 )
= 2500 × 5
= 12500 kg m/s