Answer:
a. Velocity
Explanation:
The slope of the tangent line on a position-time graph is the instantaneous velocity.
To calculate the initial velocity of the bike, we use the following equation
.
or

Here, u is initial velocity, v is final velocity, t is the time and d is the distance covered by bike.
Given,
,
and
.
Substituting these values in above equation, we get
.
Thus, the initial velocity of the bike is 1.2 m/s.
Technically you can go forever on and on, but maybe your question was like how many rotations in a certain distance?
Q stands for heat energy (Joules) hope this helps!
if one of the charge is doubled, the electric potential energy would be doubled too