A particle is projected horizontally with speed 20 m/s from the top of a 45 m high tower. Neglect air resistance and take g = 10 m/s². The magnitude of its velocity just before it strikes the ground is:
Options

Question

A particle is projected horizontally with speed 20 m/s from the top of a 45 m high tower. Neglect air resistance and take g = 10 m/s². The magnitude of its velocity just before it strikes the ground is:

Options

G1 Physics · Accepted Answer

Horizontal speed remains vₓ = 20 m/s. The vertical speed just before impact is vᵧ = √(2gh) = √(2×10×45) = 30 m/s. Hence resultant speed v = √(20² + 30²) = √1300 = 10√13 m/s. Therefore option B is correct.