What is a machine

Mechanical advantage (MA) is calculated using: $MA=\frac{\text{Load force (output)}}{\text{Effort force (input)}}$ Here, the load force is 400 N and the effort force is 100 N.

$MA=\frac{400\text{ N}}{100\text{ N}}=4$ The ramp multiplies the input force by a factor of 4.

The mechanical advantage is 4, meaning the ramp allows you to use one-quarter of the force you would need to lift the box straight up. This matches the first option.

The question asks for the mechanical advantage, which compares the load force to the effort force. Load = 400 N, Effort = 100 N.

0.25 would result from dividing effort by load ($100÷400$), which is the wrong way around. MA is always load divided by effort.

300 would come from subtracting effort from load ($400-100$). Mechanical advantage is a ratio, not a difference.

40 has no basis in the calculation — it may seem plausible but does not result from any correct formula.

$MA=400÷100=$ 4. This is the only option that correctly applies the mechanical advantage formula.

The work done to raise an object is based on the force needed to lift it vertically and the vertical height gained. The formula is: $W=F\times d$ The useful work done equals the weight of the crate multiplied by the vertical height, not the ramp length.

The crate weighs 500 N and is raised 1 m vertically. $W=500\text{ N}\times 1\text{ m}=500\text{ J}$

The ramp length (4 m) relates to the effort force applied along the ramp, not the useful work output. The useful work is always force × vertical distance gained. Machines redistribute this work but cannot reduce the total.

The work done raising the crate is 500 J.

The question asks for the work done lifting the crate — this is the useful output work, calculated using the vertical height of 1 m and the crate's weight of 500 N.

2000 J comes from $500\times 4$ — using the ramp length instead of the vertical height. This confuses the effort distance with the useful work output.

125 J comes from $500÷4$, which has no physical meaning in this context.

1500 J does not correspond to any correct calculation using the given values.

$W=500\text{ N}\times 1\text{ m}=$ 500 J, using the vertical height as the relevant distance.