Question

I tried using change in momentum. How can I find Fmax?

Answer 1

This is what I get

Explanation:

In classical mechanics, impulse is the integral of a force `vecF`, over the time interval `t` for which force acts.
In the figure

`"Impulse " =" Area under the Force time graph"`
`=1/2F_maxxxDelta t`

Also, `"Initial momentum " + " Impulse " = " Final Momentum"`

Inserting given and calculated values we get

`0.2xx4-1/2F_maxxx(40xx10^-3)=0`
(`-ve` sign because both are vectors and direction of initial momentum and stopping force are opposite to each)
`=>F_max=0.8/(20xx10^-3)=40\ N`