Question

A car is moving with a constant speed of $20\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$ against resistance $100N$. The power exerted by the car is

• A. $2kW$
• B. $5W$
• C. $200W$
• D. $1kW$

Answer 1

The correct option is A

$2kW$

Step 1: Given:

Speed of car $=20\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$

Force $=100N$

Step 2: Calculate the power,

$$\begin{gathered} \Rightarrow Power=\frac{work}{time} \\ \Rightarrow Power=\frac{force\times dis\tan ce}{time}=force\times velocity \\ \Rightarrow Power=100\times 20=2000W \\ \Rightarrow Power=2kW \end{gathered}$$

Thus, the power in the given case is $2kW$.

Hence, option A is the correct answer.