⚛️ Physics · Motion in a Plane · NEET & JEE

A boat heads straight across a 300 m wide river at 5 m s-1 relative to the water, while the river flows at 4 m s-1. The downstream drift when it reaches the far bank is:

Answer: 240 m.

A 180 m
B 240 m
C 120 m
D 300 m

Correct answer: B. 240 m

Explanation: Crossing time = 300 / 5 = 60 s (the 5 m s-1 is fully across). Drift = 4 × 60 = 240 m.

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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A boat heads straight across a 300 m wide river at 5 m s<sup>-1</sup> relative to the water, while the river flows at 4 m s<sup>-1</sup>. The downstream drift when it reaches the far bank is:

Concept context

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