⚛️ Physics · Motion in a Plane · NEET & JEE

From the top of a tower 45 m high, a stone is thrown horizontally at 20 m/s. Velocity on reaching ground (g=10):

Answer: √1300 m/s.

A 20 m/s
B 30 m/s
C √700 m/s
D √1300 m/s

Correct answer: D. √1300 m/s

Explanation: Time to fall: 45 = ½×10×t², so t = 3 s. Vertical speed v_y = gt = 30 m/s; horizontal speed v_x = 20 m/s. Speed = √(20² + 30²) = √(400 + 900) = √1300 m/s (about 36 m/s).

Projectile trajectories launched at 15, 30, 45, 60, 75 and 90 degrees at the same speed, each annotated with range R, maximum height H and time of flight T, with coloured dots marking equal time intervals

Projectiles at equal speed: range is maximum at 45°, and complementary angles (30° and 60°) share the same range. Image: Cmglee, CC BY-SA 3.0, via Wikimedia Commons.

Concept context

Vectors, projectile motion, uniform circular motion, and relative velocity - the foundation of 2D kinematics for NEET and JEE.

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From the top of a tower 45 m high, a stone is thrown horizontally at 20 m/s. Velocity on reaching ground (g=10):

Concept context

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