Question

The velocity initial velocity of a particle moving along a straight line is 10m/sec and its retardation is 2$m/se{c}^2$. The distance moved by the particle in the fifth second of its motion is

• A. 1 m
• B. 19 m
• C. 50 m
• D. 75 m

Answer 1

The correct option is A 1 m

Given,

$u=10m/s$

$a=-2m/s^2$

$n=5$

The distance covered by the particle in $n^{th}$ second is

$S_n=u+\frac{a}{2}(2n-1)$

$S_5=10-\frac{2}{2}(2\times 5-1)$

$S_5=10-9=1m$

The correct option is A.