Question

4. A body is projected at an angle 30° to the horizontal with a speed of 30 ms-1. The
angle made by the velocity vector with the horizontal after 1.5 s is (g=10ms)
A) zero
B) 60°
C) 45°
D) 90°​

Answer 1

Answer:

(A) zero

Explanation:

Vy - final velocity at time "t" in y-direction

Vx - final velocity at time "t" in x-direction

Vx = Ux = 30 cos(30) = 15√3 m/s

Vy = Uy - gt = 30 sin(30) - 10 × 1.5

= 15 - 15 = 0

that means, body is at its highest point.

so, angle with horizontal = 0°

or,

tan(¢) = Vy / Vx = 0

=> ¢ = 0°