The position of an object moving along x-axis is given by `x=a+bt^(2)` where `a = 8.5 m, b = 2.5 m s^(-2)` and t is measured in seconds. What is its velocity at t = 0 s and t = 2.0 s. What is the average velocity between t = 2.0 s and t = 4.0 s ?

Options

A. Velocity at t=2 see is zero
B. average velocity between t=2, t=4 sec is 15 m/s.
C. velocity at t =4 sec is 10 m/s
D. all the above are true

Answer

B