Question

A body is projected at an angle of $30^\circ $ with the horizontal and with a speed of $30ms^{- 1}$ . What is the angle with the horizontal after $1.5$ seconds? (Take $g=10ms^{- 2}$ )

• A. $0^\circ $
• B. $30^\circ $
• C. $60^\circ $
• D. $90^\circ $

Answer 1

Answer: (A)

The time of flight is given by :
$T=\frac{2 u sin \theta }{g}=\frac{2 \times 30 \times 1}{10 \times 2}=3sec$
Thus, after 1.5 sec the body is at the highest point. As the direction of motion is horizontal after $1.5$ seconds, the angle with the horizontal is $0^\circ .$