Question

The velocity of a particle moving with constant acceleration at an instant $t_0$ is $10m/s$. After $5$ seconds of that instant the velocity of the particle is $20m/s$. The velocity at $3$ second before $t_0$ is:

• A. $8m/s$
• B. $6m/s$
• C. $4m/s$
• D. $7m/s$

Answer 1

The correct option is C $4m/s$

Acceleration$=\frac{(v-u)}{t}$

$=\frac{(20-10)}{5}$

$=2m/s^2$

Now,

$v=u+at$

$10=u+(2\times 3)$

$u=10-6$

$u=4m/s$

The velocity at 3 sec before is 4 m/s