Why is the motion of an athlete moving along a circular path considered an accelerated motion?

An electron moving with a velocity of $5 \times 10^{4} \, ms^{-1}$ enters into a uniform electric field and acquires a uniform acceleration of $10^{4} \, ms^{-2}$ in the direction of its initial motion.
$(i)$ Calculate the time in which the electron would acquire a velocity double of its initial velocity.
$(ii)$ How much distance the electron would cover in this time?

Name the force which is responsible for change in position or state of an object.

$(a)$ Derive graphically the equation for velocity$-$time relation.
$(b)$ Name the device used to measure distance travelled by a vehicle.
$(c)$ Can displacement of a moving object be zero? Give reason.

What does the slope of the velocity$-$time graph represent?

Mention the nature of motion of a body if its displacement$-$time graph is a straight line parallel to the time axis.