The velocity y of a particle in a time t is given by the equation. y = 10 + 2t². Find the instantaneous acceleration after 5 seconds?

A. 60 ms−²
B. 20 ms−²
C. 15 ms−²
D. 10 ms−²

Correct Answer:

Option B – 20 ms−²

Explanation

The velocity V = 10 + 2t²
But acceleration, a = dv/dt
thus if V = 10 + 2t²
dv/dt = 4t
And t = 5s then a = 4×5 = 20m/s²
∴a = 20m/s²