Question

7. A ball is pushed with an initial velocity of4.0 m/s. The ball rolls down a hill with aconstant acceleration of 1.7 m/s2. The ballreaches the bottom of the hill in 5.0 s. Whatis the ball's velocity at the bottom of thehill?A. 10 m/sB. 8 m/sC. 13 m/sD. 11 m/s

Answer 1

Given data:

* The initial velocity of the ball is 4 m/s.

* The constant acceleration of the ball is,

`a=1.7ms^(-2)`

* The time taken by the ball is 5 s.

Solution:

By the kinematics equation, the final velocity of the ball in terms of the initial velocity, time, and acceleration is,

`v-u=at`

where v is the final velocity, u is the initial velocity, a is the acceleration and t is the time,

Substituting the known values,

`\begin{gathered} v-4=1.7*5 \\ v-4=8.5 \\ v=8.5+4 \\ v=12.5ms^(-1) \end{gathered}`

The closest value of the final velocity is 13 m/s.

Hence, option C is the correct answer.