Question

[Assume g = 10m/s?] If a girl is running along a straight road with a uniform velocity 1.5 m/s, find her acceleration. (Ans: 0) a.​

Answer 1

velocity after 2 seconds?

I assume the units are wrong: a = 2 m/s/s, not 2 m/s.

That means the each second, speed increases by 2 m/s. So, after 1 second, it’s going 2 m/s and after 2 seconds, it’s going 4 m/s. As long as the acceleration continued, each seconds would result in a gain of 2 m/s. You could just plug this into:

Vf = Vi + at.

Thus, Vi = 0 and Vf = 4 m/s.

The average speed during these 2 seconds is the average of initial and final speeds:

Vavg = (0 + 4)/2 = 2 m/s

The means that during these 2 seconds, on AVERAGE the bus was going 2 m each second. During the first second, it was going slower than 2 m/s and during the last second it was going faster than 2 m/s, but on AVERAGE, it was going 2 m each second. This is 2m + 2m = 4 m.

You could just plug the numbers into an equation:

X = Vi x t + 1/2 at^2 = 0 + 1/2 x 2 x 2^2 = 0 + 4 = 4 m

So, in conclusion:

the units needed to be corrected

Vf = 2 m/s (this is speed, which is the AMOUNT of velocity, since velocity requires a direction)

Distance = 4 m

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Answer 2

Her acceleration is 0 m/s²

Step-by-step explanation:

We note that the motion of the girl is on a straight road, therefore;

The vertical acceleration (e.g. due to gravity, g) on the horizontal motion = 0

The horizontal acceleration, a = (Change in velocity, Δv)/(Change in time, Δt)

For uniform velocity, the change in velocity, Δv = 0

Therefore, fore any change in time, Δt, we have;

a = Δv/Δt

Her acceleration, a = 0/Δt = 0

Her acceleration, a = 0 m/s²