Question

A car travels from stop A to stop B with a speed of 30 km/h and then returns back to A with a speed of 50 km/h. Find :

(a) displacement of the car

(b) The average speed of the carA

(c) Total distance traveled

Answer 1

Step 1: Given

Speed from A to B = 30 km/h

Speed from B to A = 50 km/h

Let the distance between the A and B be X.

Step 2: Formula used

$Averagespeed=\frac{Totaldistancetraveled}{Totaltimetaken}$

$speed=\frac{distance}{timetaken}$

Part (a)

Step 3: Finding the displacement

Since the car travels back to the same position A, its displacement is zero.

Displacement is defined as the shortest distance between the initial and final position.

In this case, the initial position and final position of the car is the same so displacement is zero.

Part (b)

Step 4: Finding the average speed

Time taken by the car to travel from the A to B = $\frac{X}{30}$ h

Time taken by the car to travel from B to A = $\frac{X}{50}$ h

We know,

$Averagespeed=\frac{Totaldistancetraveled}{Totaltimetaken}$

Putting all the values

$Averagespeed=\frac{2X}{(\frac{X}{30}+\frac{X}{50})}$

After solving

Average speed = 37.5 km/h

Part (c)

Step 5: Finding the total distance

Total distance traveled by car = $2\times 37.5=75m$

Hence, the total distance covered by car is $75m$.