Question

calculate the average velocity of a motor cycle that travels 72km/hr in 20 seconds

Answer 1

Answer:

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20m/s

Explanation:

72kmph=20mps

t=20secs

Average velocity=Total distance /Time taken.

distance =speed x time

= 20*20

=400

Avg. vel. = 400/20

=20m/s

Hope it helps.... ✌

Answer 2

Answer:

It is long answer but hope it help's you.

Explanation:

In the absence of any more information, I would say that the average velocity is 72km/h. The 20s is irrelevant.

So I’m going to assume that you meant a motorcycle accelerating from a stop (0 velocity) to 72km/h in 20s. In this case, the average velocity is (0 + 72)/2 = 36km/h.

But let’s try a tougher question: what distance did the motorcycle cover if accelerating from a stop to 72km/h in 20s?

Let’s refer to the 4 basic kinematic equations of motion for constant acceleration ( this is today’s lesson!):

s = ut + ½ at^2

v^2 = u^2 + 2as

v = u + at

s = (u + v)t/2

where s is distance, u is initial velocity v is final velocity a is acceleration and t is time.

In this case, the simplest equation for distance is s = (u + v)t/2

Converting 72km/h to m/s, we get (72km/h x 1000m/km) / 3600s/h = 20m/s

So, s = (0 + 20) x 20/2 = 200m