Question

A projectile is thrown with initial velocity of 20 m/s at an angle of ${37}^o$ from horizontal. Time after which velocity becomes perpendicular to acceleration is

• A.
  1.2 sec
• B.
  2.4 sec
• C.
  0.5 sec
• D.
  0.6 sec

Answer 1

The correct option is A

1.2 sec
$\overrightarrow{v}$ is perpendicular to $\overrightarrow{a}$ at highest point
So $t=\frac{T}{2}=\frac{2v_{0}sin\theta }{2g}$
$t=\frac{20sin37}{10}=1.2$