Question

The driver of a car moving at 25m/s applies breakes,decelerates uniformly and stops at 10s.Another driver moving at 15m/s applies breakes,decelerates uniformly and stops at 20s.Plot a v-t graph for the 2 cars.Which of the 2 cars travelled farther after breaks were applied

Answer 1

Car B moving at 15m/s after applying brake decelerates uniformly and stops at the 20s travelled farther after breaks were applied.

• We use the formula for calculating the distance travelled by car after the brake is applied is,
• Distance travelled by car after applying brake = average velocity × time taken
• Car A  - The driver of a car moving at 25m/s applies brakes, decelerates uniformly and stops at 10s.
• Distance travelled by car A after applying brake  
• = [(25 + 0) ]/2 m/s × 10 s  = 125 m.
• Car B  - The driver of a car moving at 15m/s applies brakes, decelerates uniformly and stops at the 20s.
• Distance travelled by car B after applying brake  
• = [(15 + 0) ]/2 m/s × 20 s  = 150 m.