Question

If a ball is thrown vertically upwards and the height 's' reached in time 't' is given by $s=22t-11t^2$, then the total distance travelled by the ball is

• A. 44 units
• B. 33 units
• C. 11 units
• D. 22 units

Answer 1

The correct option is D 22 units

Height $s$ reached by the ball in time $t$ is given by $s=22t-11t^2$

Differentiating w.r.t. $t$ on both sides, we get velocity $v=\frac{ds}{dt}=22-22t$

At the topmost point, velocity has to become zero and so $22-22t=0$ gives $t=1$

Thus, time taken for upward journey is 1 unit.

Distance travelled in upward journey is thus $s=22-11=11$ unit.

The same distance would be travelled by the ball in its return journey and thus, the total distance travelled becomes 22 unit.