Question

A 20. kilogram mass moving at a speed of 3.2 meters per second is stopped by a constant force of 15 newtons. For what length of time, to the nearest tenth, must the force act on the mass to stop it?

Answer 1

4.3 seconds

Explanation:

We have that the force is determined in this case by the following formula:

`F=m\cdot(\Delta v)/(\Delta t)`

We know all the values except time, therefore we can calculate time by substituting and solving for time like this:

`\begin{gathered} 15=20\cdot(3.2-0)/(\Delta t) \\ \Delta t=20\cdot(3.2-0)/(15) \\ \Delta t=4.3\text{ s} \end{gathered}`

The time would be 4.3 seconds