1.2 A bus with a mass of 5 tons decelerates from \( 25 \mathrm{~m} / \mathrm{s} \) to rest during 100 seconds due to friction only after its engine cuts out. Calculate the force of friction expenienced by the bus.

To determine the force of friction experienced by the bus, we can use Newton's second law of motion. The bus decelerates from a speed of \( 25 \mathrm{~m/s} \) to rest, meaning its final velocity is \( 0 \mathrm{~m/s} \). The mass of the bus is \( 5 \) tons, which is equivalent to \( 5000 \) kg. 1. First, calculate the deceleration: \[ a = \frac{\Delta v}{\Delta t} = \frac{0 - 25}{100} = -0.25 \mathrm{~m/s^2} \] 2. Now, apply Newton's second law: \[ F = m \cdot a = 5000 \, \text{kg} \times (-0.25 \, \text{m/s}^2) = -1250 \, \text{N} \] The negative sign indicates that the force is acting in the opposite direction of the bus's motion, confirming it's friction. Therefore, the force of friction experienced by the bus is \( 1250 \, \text{N} \).