1.

line with speed 40l A from A to B and returns back from BtoAsneed 60 km h. Find the average speedar travels along a straightооf the car and its average velocity.

Answer»

Let the Distance between A and is x km.

First Case---Initial Speed = 40 km/hr.

Using the Formula,

Speed = Distance/Time time = Distance/Speed time(t1) = x/40 hr.

In second Case,Final Speed = 60 km/hr.

Thus, time(t2) = x/60 km/hr.

For Average Speed,

Total Distance covered by the Car = x + x = 2x km.Total time = t1 + t2 = x/40 + x/60 = (4x + 2x)/120 = 6x/120 = x/20 hrs.

Using the Formula,

Average Speed = Total Distance/Total Time = 2x/(x/20) = 2x× (20/x) = 2× 20 = 40 km/hr.

Thus, Average Speed of the Car is 40 km/hr.

Thanx



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