Figure 2 shows an energy transfer diagram for a steam engine - Edexcel - GCSE Physics: Combined Science - Question 2 - 2019 - Paper 1

Using the given formula for efficiency:

$\text{efficiency} = \frac{\text{useful energy transferred by the steam engine}}{\text{total energy supplied to the steam engine}}$

Substituting the values:

$\text{efficiency} = \frac{160 \text{ J}}{2000 \text{ J}} = 0.08$

Multiplying by 100 to convert to percentage:

$\text{efficiency} = 0.08 \times 100 = 8\%$

The wasted energy is typically lost to the surroundings as heat. This loss decreases the overall energy efficiency of the steam engine.

1. Burning coal releases greenhouse gases, contributing to climate change.
2. Coal mining can cause environmental degradation, including habitat destruction and water pollution.

The formula for kinetic energy is:

$\text{kinetic energy} = \frac{1}{2} \times \text{mass} \times \text{(speed)}^2$

Substituting the values:

$\text{kinetic energy} = \frac{1}{2} \times 8.0 \text{ kg} \times (1.5 \text{ m/s})^2 = \frac{1}{2} \times 8.0 \text{ kg} \times 2.25 \text{ m}^2/\text{s}^2 = 9.0 \text{ J}$