I need help with this

Question

1.) What is the mechanical advantage of an inclined plane if its runs is 7.8 m and its rise is 3.0 m?

2.) What force is would be required to roll a barrel weighing 300 newtons up the inclined plane in the first problem?

I already answered the first question and i need help on the second one

Answer 1

For ideal mechanical advantage in all simple machines: W_in = W_out or F_id_i = F_od_o

Mechanical advantage = F_o/F_i It is the multiplier of the force you put in in order to exert a force out of the machine (usually mg - lifting a weight.

a) For ideal cases, F₀/F_i = d_i/d_o i.e. because the work must be the same in and out for a simple machine, in order to have a mechanical advantage you have to exert the F_i for a longer distance. In the case of a ramp, d_i is the slope of the ramp and d_o is the height vertical height that the weight is lifted. I assume that by run you mean the vertical distance travelled going up the ramp, so the slope is (x² + y²)^1/2.

In b you are given the F_o so you need to divide by the Ideal Mech. Adv. you calculated in (a) in order to get F_i.