Question

The position of a particle moving in a straight line along x-axis varies with time as $x = 12t - 3t^{2}$ m, where $t$ is in seconds. The distance covered by the particle in the first 5 seconds is:

1) 33m

2) 15m

3) 45m

4) 39

Answer 1

Answer ⇒ Hence, option (b).  is correct.

Explanation ⇒

x = 12t - 3t²

At time t = 0 seconds,

x = 0

At time t = 5 seconds,

x = 12 × 5 - 3 × 5²

x = 60 - 75

∴ x = -15

Thus, distance is 15 m in negative direction of x - axis.

Hence, option (b).  is correct.

Hope it helps.

Answer 2

Explanation:

The distance covered by the particle in the first 5 seconds is: 15m