Question

Any physics expert online? See the attachment. Thanks :)

Answer 1

`245 " N"`

Looks right to me.

Explanation:

The force required to overcome friction and begin motion is given by:

`F = mu N`

where `mu` is the coefficient of static friction and `N` is the normal force.

You are given a mass, which means that the normal force can be found. This is because the normal force is equivalent to the weight of the box. I will use `g = 10` m/s/s.

`N = mg = (50)(10) = 500 " N"`

We need `mu`, however there is no other values given. The question does mention a wooden box and wooden floor, so we can look up the value of the coefficient from some reference source. I went online and found that the coefficient for wood-on-wood contact is `mu = 0.25-0.5`.

I guess this range is due to the fact that there are different types of wood and whether or not the floor is sanded could impact friction. But either way, let's just use the low and high values to see the range of forces required.

For `mu = 0.25 -> F = (0.25)(500) = 125 " N"`

For `mu = 0.5 -> F = (0.5)(500) = 250 " N"`

Since there is no answer anywhere near `125`, but there is one near `250`, I would choose the answer that you selected as well: `245 " N"` (this is probably because I chose `g = 10` instead of `g = 9.8` or something).