If at any point on the path of a projectile its velocity is $u$ at inclination $\alpha$ then it will move at right angles to former direction after time
$\frac{u}{g \cos ec \alpha}$
$\frac{u}{g \sin \alpha}$
$\frac{u}{g \cos \alpha}$
$\frac{u}{g \sec \alpha}$
The trajectory of a projectile near the surface of the earth is given as$ y = 2x -9x^2$. If it were launched at an angle $\theta_0$ with speed $v_0$ then $(g = 10\, ms^{-2}$)
A projectile is thrown at an angle $\theta$ such that it is just able to cross a vertical wall at its highest point as shown in the figure.The angle $\theta$ at which the projectile is thrown is given by
A particle is projected from the ground with an initial speed $\upsilon $ at an angle $\theta $ with horizontal. The average velocity of the particle between its point of projection and highest point of trajectory is
Three identical balls are projected with the same speed at angle $30^o, 45^o$ and $60^o$. Their ranges are $R_1 R_2$ and $R_3$ respectively. Then
A ball thrown by one player reaches the other in $2$ sec. the maximum height attained by the ball above the point of projection will be about ....... $m$