Physics

Problem

A cyclist starts from rest, accelerates uniformly for

4\,\text{s}

to reach

6\,\text{m\,s}^{-1}

, and then immediately moves at a constant speed of

6\,\text{m\,s}^{-1}

for the next

4\,\text{s}

. Which one of the following comparisons is correct? a) Average velocity in the whole

8\,\text{s}

equals the instantaneous velocity at

t=8\,\text{s}

. b) Average velocity in the whole

8\,\text{s}

3\,\text{m\,s}^{-1}

. c) Instantaneous velocity at

t=2\,\text{s}

is equal to the average velocity during the first

4\,\text{s}

. d) Average velocity in the first

4\,\text{s}

equals the instantaneous velocity at

t=4\,\text{s}