Question

The position of an object moving along xaxis is given by x=a+bt² , where a = 8.5 m and b = 2.5 ms^-2 and and t is measured in second. What is the velocity at t=0 s and t=2.0 s? What is the average velocity between t = 2.0 s and t = 4.01 s?

Answer 1

Position is given as x = a + bt² = 8.5 + 2.5t²

Position at t = 2 s,

x₂​ = 8.5 + 2.5(2)²

= 18.5 m

Position at t = 4 s,

x₁​ = 8.5 + 2.5(4)²

= 48.5 m

Displacement,

S = x₂​ − x_1​

= 48.5 − 18.5

= 30 m

Time taken,

t = 4 − 2

= 2 s

Average velocity,

V_avg​ = S/t

= 30/2

= 15 m/s

Answer 2

Average velocity =  displacement/time