Ten questions. The result tells you which lessons you may skip.
The Moon goes round the Earth. A student's free-body diagram of the Moon shows the Earth's gravity towards the Earth and a centripetal force towards the Earth. The diagram is
A \(0.5\,\text{kg}\) stone goes round a smooth table at \(4\,\text{m/s}\) on a \(1\,\text{m}\) string tied to a peg. The tension in the string is
The string of a whirled stone on a smooth table breaks. The stone then moves
A car of mass \(800\,\text{kg}\) crosses the top of a hump of radius \(40\,\text{m}\) at \(10\,\text{m/s}\). Take \(g = 10\,\text{m/s}^2\). The normal force on it at the top is
A car on a hump of radius \(R\) just loses contact with the road at the top. Its speed is
Two conical pendulums have the same string length and the same angle, but one bob is twice as heavy. Their periods are
In a rotor of radius \(4\,\text{m}\) with \(\mu_s = 0.4\) between rider and wall, the floor can be lowered once the angular speed is at least
On a flat turn, the greatest safe speed is \(v\). The same road, with the same tyres, curves on a radius four times as large. The greatest safe speed there is
A road of radius \(90\,\text{m}\) is banked with \(\tan\theta = 0.25\). Take \(g = 10\,\text{m/s}^2\). The speed at which no friction is needed is
A block rests on a turning platform, and you describe it from the ground. The forces you draw on it are