Question

how much work is needed to be done on a ball mass 50g to give it a momentum of 5kg m s^-1.​

Answer 1

Answer:

50 J.

Explanation:

We know,

   Work done = change in kinetic energy.

Here,

⇒  K.E = 1 / 2 mv^2      { we know }

⇒ K.E = 1 / 2 [ mv ]^2 / m

⇒ K.E. = 1 / 2 ( p )^2 / m        { mv = p = momentum }

⇒ K.E = p^2 / 2m

⇒  K.E = ( 5 ) / ( 2 x 50 / 1000 ) J

⇒  K.E = 5 / ( 2 x 0.05 ) J

⇒  K.E = 5 / ( 0.1 ) J

⇒  K.E = 50 J

Work needed  = 50 J