Question

A car of mass 1250 kg is moving at 30m/s. Its engine delivers 30 kW while resistive force due to surface is 750N. What max acceleration can be given in the car

• A. $\frac{1}{3}m/s^{2}$
• B. $\frac{1}{4}m/s^{2}$
• C. $\frac{1}{5}m/s^{2}$
• D. $\frac{1}{6}m/s^{2}$

Answer 1

Answer: (C)

$\frac{1}{5}m/s^{2}$

Answer 2

Force produced by the engine $F = \frac { P } { v } = \frac { 30 \times 10 ^ { 3 } } { 30 }$ =10³N

Acceleration =$\frac { \text { Forward force by engine } - \text { resistive force } } { \text { mass of car } }$

$= \frac { 1000 - 750 } { 1250 } = \frac { 250 } { 1250 }$= $\frac { 1 } { 5 } m / s ^ { 2 }$