Question

A man throws a ball at height of 10 m at an angle of ${35}^o$ from horizontal. If mass of ball is 0.5 kg and its initial speed is 30 m/s.
$g=-9.8\frac{m}{s^2}$
At what angle to the horizontal will the ball impact the ground?

• A. ${33.5}^o$
• B. ${17.1}^o$
• C. ${21.1}^o$
• D. ${44.3}^o$
• E. ${41.99}^o$

Answer 1

The correct option is E ${41.99}^o$

The vertical velocity that the ball would have gained in this time will be found using the equation of motion $v^2-u^2=2as$

$⟹v^2-(-30\times sin{35}^{\circ }{)}^2=2(9.8\left)\right(10)$

$⟹v_y=22.18m/s$

The horizontal component of speed remains the same since there is no force acting on ball in horizontal direction.

Thus $v_x=30\times cos{35}^{\circ }m/s=24.57m/s$

The angle the ball's velocity makes with the horizontal=$ta{n}^{-1}\left(\frac{v_y}{v_x}\right)\approx {41.99}^{\circ }$