1. 20 m/s, 5 m/s ² 2. 20 m/s, 0 3. 20√(2) m/s, 0 4. 20√(2) m/s, 10 m/s ²

Topic: Projectile motion· Kinematics

A car starts from rest and accelerates at 5 m/s^2. At t = 4 s, a ball is dropped out of a window by a person sitting in the car. What is the velocity and acceleration of the ball at t = 6 s ? (Take g = 10 m/s^2)

1. 20 m/s, 5 m/s\(^2\)

2. 20 m/s, 0

3. \(20\sqrt{2}\) m/s, 0

4. \(20\sqrt{2}\) m/s, 10 m/s\(^2\)

Doubtly Asked 30 Oct 2026 NEET UG 2021 Practice test neet Save WhatsApp Report

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Answer: 4. \(20\sqrt{2}\) m/s, 10 m/s\(^2\)

Key idea: once the ball is dropped, its horizontal velocity stays equal to the car's velocity at that instant, and only gravity acts (acceleration 10 m/s\(^2\) downward).

At t = 4 s car speed \(=5\times4=20\) m/s, so \(v_x=20\) m/s.
In the next 2 s: \(v_y=gt=10\times2=20\) m/s.

\(v=\sqrt{20^2+20^2}=20\sqrt2\) m/s, acceleration \(=g=10\) m/s\(^2\). Option 4.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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A car starts from rest and accelerates at 5 m/s^2. At t = 4 s, a ball is dropped out of a window by a person sitting in the car. What is the velocity and acceleration of the ball at t = 6 s ? (Take g = 10 m/s^2)

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