Question

A particle at rest starts moving with uniform acceleration covers a distances $114$ meters in $8^{th}$ second. The acceleration of the particle is

• A. $20m/s^2$
• B. $15m/s^2$
• C. $14.5m/s^2$
• D. $15.4m/s^2$

Answer 1

The correct option is D $15.4m/s^2$

We know that,
$s=ut+\frac{1}{2}a{t}^2$
Distance covered in $7$ seconds,
$s_7=7u+\frac{49a}{2}$
Distance covered in $8$ seconds,
$s_8=8u+\frac{64a}{2}$
It starts from rest, so $u=0$
$s_8-s_7=\frac{15a}{2}\Rightarrow 114=\frac{15a}{2}\Rightarrow a=15.2m/s^2$