Question

The position of a particle moving on a straight line path is given by x = 12 + 18t + 9t² meter its velocity at t = 2 s is

(a) 84 ms^-1

(b) 72 ms^-1

(c) 54 ms^-1

(d) 36 ms^-1

Answer 1

Answer is (c) 54 ms^-1

Velocity = dx/dt = 18 + 18t.

It depends upon time. For t = 2s, the velocity = 18 +18 x 2 ms^-1 = 54 ms^-1