Skip to content
doubtly
Topic: Kinetic and potential energy, work-energy theorem· Work, Energy and Power

A toy car with charge q moves on a frictionless horizontal plane surface under the influence of a uniform electric field E. Due to the force q E, its velocity increases from 0 to 6 m/s in one second duration. At that instant the direction of the fiel…

A toy car with charge q moves on a frictionless horizontal plane surface under the influence of a uniform electric field \(\vec E\). Due to the force \(q\vec E\), its velocity increases from 0 to 6 m/s in one second duration. At that instant the direction of the field is reversed. The car continues to move for two more seconds under the influence of this field. The average velocity and the average speed of the toy car between 0 to 3 seconds are respectively

1. 2 m/s, 4 m/s

2. 1 m/s, 3.5 m/s

3. 1 m/s, 3 m/s

4. 1.5 m/s, 3 m/s

1 answer

Best answer

Answer: 3. 1 m/s, 3 m/s

Phase 1 (0 to 1 s): \(a=6\ \mathrm{m/s^2}\), displacement \(=\tfrac12\cdot6\cdot1=3\) m, ending at 6 m/s.

Phase 2 (1 to 3 s): the acceleration reverses to \(-6\ \mathrm{m/s^2}\). The car decelerates to rest after 1 s, covering 3 m more, then moves backward for 1 s covering 3 m.

Net displacement \(=3+3-3=3\) m. Total path \(=3+3+3=9\) m.

Average velocity \(=3/3=1\) m/s. Average speed \(=9/3=3\) m/s.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report
Was this answer helpful?

Your answer

Log in or create a free account to answer this question.