Question

a car travel from stop A to B with the speed of 30 km per hour and then return back to a with a speed of 50 km per hour find
1.displacement of the car
2.distance travel by car 3.average speed of car​

Answer 1

Answer :

Given -

• The car travel from stop A to B with a speed of 30 km/hr.
• Then it return to stop A with a speed of 50 km/hr.

To Find -

• Displacement ?
• Distance ?
• Average Speed ?

Solution -

As, the car returns to be first stop again, the displacement of the car is 0 km or 0 m.

The distance distance travelled by the car will be double the distance of between Stop A and B.

Let us assume the Distance between stop A and B as d.

First case :

Time 1 = d/30 s

Second case :

Time 2 : d/50 s

Hence, Average Speed = Total Distance/Total Time

⇒ Avg. Speed = (d + d)/(d/30 + d/50)

⇒ Avg. Speed = 2d/[(50d + 30d)/1,500]

⇒ Avg. Speed = 2d * 1,500/80d

⇒ Avg. Speed = 1,500/40

⇒ Avg. Speed = 150/4

⇒ Avg. Speed = 37.5 km/hr OR Avg. Speed = 10.41 m/s

FINAL ANSWERS :

• Distance = 2d km
• Displacement = 0 km
• Average Speed = 37.5 km/hr