Question

A stone is projected from the ground with velocity 50 m/s at an angle 30° with horizontal. It crosses a wall after 3 s. How far beyond the wall the stone will strike the ground? ($g = 10 m/s²$)

• A. 90.2 m
• B. 12.5 m
• C. 86.5 m
• D. $125\sqrt3$ m

Hint:

Range = horizontal velocity × total time of flight.

Answer 1

The Correct Option is C

Step 1: Horizontal velocity $vₓ = 50 \cos30^\circ = 25\sqrt3$.

Step 2: Total time of flight $T = \frac2 × 50 \sin30^\circ10 = 5 s$.

Step 3: Total range $= vₓ × T = 25\sqrt3 × 5 ≈ 216.5 m$.

Step 4: Distance at wall (3 s) $= 25\sqrt3 × 3 ≈ 130 m$.

Step 5: Beyond wall $= 216.5 - 130 = 86.5 m$.