The position vector of a particle is given as $\vec r\, = \,({t^2}\, - \,8t\, + \,12)\,\hat i\,\, + \,\,{t^2}\hat j$ The time after which velocity vector and acceleration vector becomes perpendicular to each other is equal to........$sec$
$1$
$2.5$
$2$
$1.5$
The height $y$ and the distance $x$ along the horizontal plane of a projectile on a certain planet (with no surrounding atmosphere) are given by $y = (8t - 5{t^2})$ meter and $x = 6t\, meter$, where $t$ is in second., the acceleration due to gravity is given by ......... $m/{\sec ^2}$
A particle is moving eastwards with a speed of $6 \,m / s$. After $6 \,s$, the particle is found to be moving with same speed in a direction $60^{\circ}$ north of east. The magnitude of average acceleration in this interval of time is ....... $m / s ^2$
A ball is rolled off along the edge of a horizontal table with velocity $4 m/s$. It hits the ground after time $0.4 \,\,s$. Which of the following are correct?