Question

A mass of 35kg inside a 15kg wagon is pulled by a man across a sandy beach with a coefficient of .25, if the pulling force is 250N, at an angle 25 degrees above the horizontal, how do you determine the net force?

can you determine the net force, force of friction, net force on the wagon, acceleration of the wagon, and how long it takes the man to pull the wagon 100m if it began at rest?

Answer 1

Resolve forces between horizontal and vertical components

Explanation:

Assuming the man is pulling the wagon...

The force of friction can be calculated as
`"Friction"=muN`

Where `mu` is the coefficient of friction which we are given as 0.25 and N is the normal reaction

We can calculate the weight as
`W=mg=50kg times 9.81=490.5N`

The wagon is not moving in the vertical direction so the following must hold:

`"Force". sin 25^0+N = weight`

`250.sin25^0+N=490.5`

So N = 384.8N

Hence friction = `384.8times 0.25=96.2N`

So net force in horizontal direction is:

`"Force".cos25^0-96.2N=130.4N`

Acceleration is given by Newton's 2nd law `F=ma`

`a=F/m=130.4/50=2.61ms^-2`

The time to travel 100m from rest can be found using

`s=ut+1/2at^2`
`u=0, s=100m, a=2.61 ms^-2`
so

`100=1/2times2.61timest^2`

So t=8.75s