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 (i) displacement of the car. (ii) distance travelled by the car. (iii) average speed of the car.
Answers
Let the distance from A to B be x.
Then displacement of the car when it comes back to the same position is zero.
Distance travelled is 2x.
Time taken by the car when it moves from A to B is given by
t1 = Distance/Speed = x/30
Time taken by the car when it moves from B to A,
t2 = Distance/Speed = x/50
Total distance = 2x
Total time
= t1 + t2
= x/30 + x/50
= (5x + 3x)/150
= 8x/150
So, Average speed
= Total distance/Total time
= 2x/(8x/150)
= 37.5 km/hr
Answer:
Displacement is the shortest distance between the initial and the final position. Here, the car travels from stop A to B and returns to stop A.
Thus, the displacement of the car is 0 m/s.
let the distance travelled by the car from stop A to B = x km
The car travels from A to B and returns back to B. Thus,
total distance travelled = 2x km
Time while going from A to B = Distance travelled / Speed taken
= x/30 hours
Time while returning from stop B to A = x/50 hours
next see the above picture
