Question

A \(1000\,\text{kg}\) car moves at \(20\,\text{m s}^{-1}\). The power required to maintain this speed against a resistive force of \(500\,\text{N}\) is

• A. \(5\,\text{kW}\)
• B. \(10\,\text{kW}\)
• C. \(20\,\text{kW}\)
• D. \(50\,\text{kW}\)

Hint:

For motion at constant speed, \[ P=Fv. \] Here \(F\) is the force opposing the motion and \(v\) is the speed of the body.

Answer 1

The Correct Option is B

Concept: Power \(P = Fv\). \(F=500\) N, \(v=20\) m/s. \(P = 500\times20 = 10000\) W = 10 kW.

Step 1: Write the final answer. \(\boxed{P=10\,\text{kW}}\)