Question

a car moves north at a constant speed of 3 ms^-1 for 20 s and then east at a constant speed of 4ms^-1 for 20s. What is the average speed of the car during this motion?​

Answer 1

Given:

A car moves north at a constant speed of 3 ms^-1 for 20 s and then east at a constant speed of 4ms^-1 for 20 s

To find:

The average speed of the car

Solution:

The distance covered by the car when it moves towards north

Dis = speed×time

• D1 = 3×20
• D1 =60 m

The distance covered by the car when it moves towards the east

Dis = speed×time

• D2 = 4×20
• D2 = 80m

The average speed of the car is given by

Total distance travelled / Total time taken

• 60+80 / 20+20
• 140 / 40
• 14/4
• 7/2
• 3.5 m/sec

So the average speed of the car is 3.5 m/sec