U2.10 – Moments

The diagram above shows a uniform rod of negligible mass. At which position on the rod is no moment exerted?

A 75 N force is applied to the end of a spanner that is 25 cm long. Calculate the size of the moment?

If an object is on its pivot, what can be said about the moments?

The diagram shows four different combinations of a baby’s mobile with four different weights: 1 N, 2 N, 3 N and 4 N. All the stars are horizontally 50 mm apart. Select the mobile that would be perfectly balanced.

You're down the allotment and are carrying your 65 kg Nana in a 20kg wheelbarrow. Your Nana's and the wheelbarrow's weight acts 60 mm from the centre of the wheel. What force do you need to apply to the end of the handle, 1.2 m from the centre of the wheel, to move your Nana about? g = 9.81 ms^-2

The diagram shows Harry and Dudley on a see-saw. Harry is sat 120 cm away from the pivot. How far away from the pivot must Dudley sit to balance with Harry?

A uniform plank GD has mass 13 kg and length 1.8 m. A mass 6.8 kg is attached to the plank at D. The plank remains balanced due two ropes attached The tension in the rope at G is half the tension of the the rope at A, calculate the tension in the rope at A. g = 9.81 ms^-2

This diagram shows the direction of force for four students pushing on a door at different distances from the hinge, d_pivot. Which student is applying the greatest moment?

A window cleaner leans her ladder against a vertical wall in order to start work. The ladder has a length of 6 m and mass of 15 kg, she places it at an angle of 50°. Calculate the reaction force from the wall at W. g=9.81 ms_-2

A 0.3 m long screwdriver is placed under the circular lid of a paint can and a force of 15 N is applied downward at the end of the screwdriver and the lid opens, pivoting at the opposite side to the screwdriver. The lid has a circumference of 48 cm. Calculate the moment about the open side of the lid.