Question

a body is projected with a velocity of 40 metre per second at an angle of 30degree with horizontal.time it takes to be at height of 20 m is

Answer 1

Answer: 2 seconds

Explanation:

For a projectile equation of motion along y-axis is

y = u*(sin theta)*t - 1/2*g*(t square)

20= 40*sin 30*t - 1/2*10*(t square)

20=20 t - 5(t square)

4= 4t - 5(t square)

after solving by quadratic formula, t = 2 seconds