Give three examples of the use of inclined planes in everyday life. 2. A heavy slab weighing 100 N is lifted to a vertical height of 5 m by applying an effort force of 400 N over a distance of 10 m. C

i) Three examples of the use of inclined planes in everyday life are:

• Ramps used for moving heavy objects or for wheelchair access.
• Wedges, such as an axe blade or a knife, used for splitting or cutting.
• Screws, which are essentially inclined planes wrapped around a cylinder, used for fastening or lifting.

ii)
Given:
Effort force ($F_E$) = 400 N
Distance moved by effort ($d_E$) = 10 m
Load force ($F_L$) = 100 N (interpreted as the weight of the slab)
Vertical height lifted ($h$) = 5 m

α) Work output
Work output is the useful work done on the load, which is the potential energy gained by lifting the slab vertically.

$$W_{out} = F_L \times h$$ $$W_{out} = 100 \text{ N} \times 5 \text{ m}$$ $$W_{out} = 500 \text{ J}$$

The work output is $\boxed{\text{500 J}}$.

β) Work input
Work input is the work done by the effort force over the distance it acts.

$$W_{in} = F_E \times d_E$$ $$W_{in} = 400 \text{ N} \times 10 \text{ m}$$ $$W_{in} = 4000 \text{ J}$$

The work input is $\boxed{\text{4000 J}}$.

γ) Efficiency
Efficiency is the ratio of work output to work input, expressed as a percentage.

$$\text{Efficiency} = \frac{W_{out}}{W_{in}} \times 100\%$$ $$\text{Efficiency} = \frac{500 \text{ J}}{4000 \text{ J}} \times 100\%$$ $$\text{Efficiency} = 0.125 \times 100\%$$ $$\text{Efficiency} = 12.5\%$$

The efficiency is $\boxed{\text{12.5\%}}$.