A car travels from stop A to stop B with a speed of 30km/h and then returns back to stop A with a speed of 50km/h. Find:
(i) Displacement of the car.
(ii) Average speed of the car.
Answers
A car travels from stop A to stop B with a speed of 30km/h and then returns back to stop A with a speed of 50km/h.
We have to find the-
(i) Displacement of the car.
(ii) Average speed of the car.
Assume that the distance covered by the car is x km.
(i) Since the car starts from point A to B and then returns back to point A again using the same pathway. Final and initial of the car is same i.e. A point.
Therefore, the Displacement of the car is 0 km.
(ii) Average speed is defined as the ratio of total distance covered with respect to total time taken.
As the distance covered by the car is same i.e. x km. From A to B distance covered is x km and from B to A distance covered is x km. So, the total distance covered by the car is 2x km.
Also,
Time = Distance/Speed
t1 = x/30 hr and t2 = x/50 hr
Total time taken = t1 + t2
= x/30 + x/50
= x/5(4/15)
= 4x/75
Average speed = 2x/(4x/75)
= (2*75)/4
= 37.5
Therefore, the average speed of the car is 37.5 km/hr.
▪ A car travels from stop A to stop B with a speed of 30 km/hr and then returns back to stop A with a speed of 50 km/hr.
▪ Find-
❶ Displacement of the car
❷Average speed of the car
✯ SOLUTION: -
❶Displacement of the car
➡ Displacement- iT is the shortest distance between initial and final position of a moving object.
▪ since, it's given in the question that the car finally returns back to stop A from where it has initially started.
Thus, the final and initial position of the car is same.
Therefore,
➡ Displacement of the car = 0
❷Average speed of the car
➡ Average speed - The average speed of an object is the total distance traveled by the object divided by the elapsed time to cover that distance.
• let the distance between Stop A and stop B be x km
Since, the car finally returns back at stop A
• total distance covered by the car =
2x km
➟ From Stop A to Stop B....
Distance = x km
Speed = 30 km/hr
Time taken = x/30 hr
➟ From Stop B to Stop A...
Distance = x km
Speed = 50 km/hr
Time taken = x/50 hr
➡ total time taken = x/30 hr + x/50 hr
= (5x+3x)/150 hr
= 8x/150 hr
☆average speed = total distance covered/ total time taken
= ( 2x km) / (8x/150 hr)
= ( 150/4) km/hr
= 37.5 km/hr
Therefore,
➡ Average speed of the car = 37.5 km/hr