Question

Please tell how can I get the answer for this question as 0.125 Newtons? I asked some physics teachers but they all are saying it's answer is 125.Please say how can I get the answer as 0.125 N?

Answer 1

The average acceleration of an object is given by:

`a=(v_f-v_0)/(t)`

In this case we know that the final velocity is zero (since it comes to rest), the initial velocity is 25 m/s and the dime is 0.03 seconds. Then the acceleration is:

`\begin{gathered} a=(0-25)/(0.03) \\ a=-833.33 \end{gathered}`

In this case the minus sign means that the ball is stopping.

Now that we have the acceleration we can apply Newton's second law:

`F=ma`

to determine the force; in this case the mass is 0.150 kg (we need to use kilograms) and the acceleration is 833.33 m/s^2 (since we are calculating the magnitude we drop the minus sign); then the force is:

`\begin{gathered} F=(0.150)(833.33) \\ F=125 \end{gathered}`

Therefore the force is 125 N.