Question

A particle is moving in a straight line under constant acceleration of 4 metre per second square if its velocity at time is equal to zero is 10 M per second the displacement of particle is the fifth second of its motion is

Answer 1

Motion in fifth second will be motion performed after 4 seconds and upto 5 seconds.
Thus you can find it by finding displacements after 5 second and 4 seconds and subtracting them.

or u can simply use formula of displacement in nth second for uniformly accelerated rectilinear motion.

Hope! it will be helpful.