Question

A particle is projected vertically upward with initial velocity 25 ms^-1. During third second of its motion, which of the following statement is correct?

• A. Displacement of the particle is 30 m
• B. Distance covered by the particle is 30 m
• C. Distance covered by the particle is 2.5 m
• D. None of these

Answer 1

Answer: (C)

Distance covered by the particle is 2.5 m

Answer 2

Displacement of the particle during third second of the motion (i.e. between t = 2s and t = 3s) is zero. Hence t = 2.5 sec is the turning point of the motion.

For distance S_{t = 2} = 25 × 2 − $\frac{1}{2}$ × 10 × 2² = 30 m

and S_t=2.5 = 25 × 2.5 − $\frac{1}{2}$ × 10 × 2.5² = 31.25 m

Hence distance covered by the particle during third second of motion = 2 (31.25 − 30) = 2.5 m,

Hence (3) is correct.