Question

A body projected from the bottom of a smooth inclined plane with a velocity $9.8m/sec$. The angle of inclination of the plane is ${30}^o$. If it comes to rest after reaching the top of the plane, then the time of ascent is

• A. $2sec$
• B. $1sec$
• C. $0.5sec$
• D. $1.5sec$

Answer 1

The correct option is A $2sec$

Retardation along the plane is $a=-gsin{30}^o=-0.5g=-4.9m/s^2$

$v=u+at$, where $v=0andu=9.8$

So, $t=2sec$