I know for sure that the third one is correct
Initial velocity (u) = 2 m/s
Acceleration (a) = 10 m/s^2
Time taken (t) = 4 s
Let the final velocity be v.
By using the equation,
v = u + at, we get
or, v = 2 + 10 × 4
or, v = 2 + 40
or, v = 42
The final velocity is 42 m/s.
I think its " both have level surfaces"
The centripetal force acts upon an object moving in a circle at constant speed. The centripetal force acts perpendicular to the direction of motion , the speed of object will remain constant.
The answer will be C, a stopwatch :)