2 The total mass of a cyclist and his cycle is 80 kg . The resistance to motion is zero.
- The cyclist moves along a horizontal straight road working at a constant rate of \(P \mathrm {~W}\). Find the value of \(P\) given that the cyclist's speed is \(5 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) when his acceleration is \(1.2 \mathrm {~m} \mathrm {~s} ^ { - 2 }\).
- The cyclist moves up a straight hill inclined at an angle \(\alpha\), where \(\sin \alpha = 0.035\). Find the acceleration of the cyclist at an instant when he is working at a rate of 450 W and has speed \(3.6 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).