... time = (25 ms-1 + 0 ms⁻¹)2 x 30 s = 12.5 ms⁻¹ x 30 s = 375 m$

The average speed of the bus is $\boxed{\text{21.25 ms}^{-1}}$.

c) Estimate the heat gained by the brake pad.

• Mass of brake pad ($m$) = $200 \text{ g} = 0.2 \text{ kg}$
• Initial temperature ($T_1$) = $40^\circ\text{C}$
• Final temperature ($T_2$) = $80^\circ\text{C}$
• Specific heat capacity ($c$) = $1000 \text{ Jkg}^{-1}\text{K}^{-1}$

Since a change of $1^\circ\text{C}$ is equal to a change of $1 \text{ K}$, $\Delta T = 40 \text{ K}$.

The heat gained by the brake pad is $\boxed{\text{8000 J}}$.