Question

A men drives 140 km in 7 hr if he does not speed up or slow down.What is the speed and the acceleration of the men.

Answer 1

speed = distance\time

= 140\7

= 2km\h

acceleration = v-u\t

= 140-140\7

= 0\7 = 0km\hr

Answer 2

The speed of the man is 20 km/hr.

The acceleration of the man is zero.

Given: The distance covered = 140 km, Time taken = 7 hr

The driver does not speed up or slow down.

To Find: The speed and the acceleration of the driver.

Solution:

• We can find the speed of the body by the formula,

        Speed = Distance / time                           ...(1)

• Whenever the velocity of a body is constant ( which means it neither speeds up nor speeds down ), the acceleration of the body is zero.

Coming to the numerical, we have;

      The distance covered = 140 km, Time taken = 7 hr

Putting respective values in (1), we get;

        Speed = Distance / time  

 ⇒    Speed = 140 / 7

                    = 20 km/hr

Again it is said that the driver does not speed up or slow down, which means that the speed is constant, hence the acceleration is zero.

Hence, The speed of the man is 20 km/hr.

            The acceleration of the man is zero.

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