6 A cyclist freewheels, with a constant acceleration, in a straight line down a slope. As the cyclist moves 50 metres, his speed increases from \(4 \mathrm {~ms} ^ { - 1 }\) to \(10 \mathrm {~ms} ^ { - 1 }\).
- Find the acceleration of the cyclist.
- Find the time that it takes the cyclist to travel this distance.
- The cyclist has a mass of 70 kg . Calculate the magnitude of the resultant force acting on the cyclist.
- The slope is inclined at an angle \(\alpha\) to the horizontal.
- Find \(\alpha\) if it is assumed that there is no resistance force acting on the cyclist.
- Find \(\alpha\) if it is assumed that there is a constant resistance force of magnitude 30 newtons acting on the cyclist.
- Make a criticism of the assumption described in part (c)(ii).