Question

Please answer the physics question fast

Answer 1

Work done by the block = kinetic energy of the bullet

                                        = 1/2 mv²

we know that, work = force x displacement.

F x d = 1/2 mv²

m x a x d = 1/2mv²

a x d = v²/2

a = v²/2d

a = 1600/ 2 x 4 x 10⁻²

a = 200/10⁻²

a = 2 x 10⁴ m/s²

now, using kinematic equation,

v = u + at

0 = u -at

u = at

t = u/a

 = 40/2 x 10⁴

t = 2 x 10⁻³ s

This is the required answer.