Question

A car increases its speed from 20km/h to 50 km/h in 10s. Its acceleration is :

• A. 30 m/s²
• B. 3 m/s²
• C. 18 m/s²
• D. none of these

Answer 1

The correct option is D

none of these

Step 1: Given data

1. Final velocity(v) $=50km/h\frac{125}{9}m/s$.
2. Initial velocity(u) $=20km/hr=\frac{50}{9}m/s$.
3. Time taken is 10 seconds.

Step 2: Calculating the acceleration of the car

We know that,

$Acceleration\left(a\right)=\frac{Changeinvelocity}{Timetaken}$

$\mathrm{a}=\frac{\mathrm{v}-\mathrm{u}}{\mathrm{t}}=\frac{{\displaystyle \frac{125}{9}}-{\displaystyle \frac{50}{9}}}{10}=\frac{{\displaystyle \frac{75}{9}}}{10}=0.833\mathrm{m}/{\mathrm{s}}^2$.

Therefore, the acceleration is 0.833 m/s²,

Hence, the correct option is (D).