# Physics Topic: Forces

Recall and apply Hooke’s law in problem solving.

Deduce the elastic potential energy in a deformed material from the area under the force-extension graph.

Describe the forces on mass, charge and current in gravitational, electric and magnetic fields.

Solve problems using the pressure formula.

*Show an understanding of the origin of the upthrust acting on a body in a fluid.

*State that an upthrust is provided by the fluid displaced by a submerged or floating object.

*Calculate the upthrust in terms of the weight of fluid displaced.

*Recall and apply the principle that, for an object floating in equilibrium, the upthrust is equal to the weight of the object to new situations or to solve related problems.

Show a qualitative understanding of frictional and viscous forces including air resistance, (No treatment of coefficient of friction and viscosity is required.)

Use a vector triangle to represent forces in equilibrium.

Show an understanding that the weight of a body may be taken as acting at a single point known as its centre of gravity.

Understand a couple as a pair of forces tending to produce rotation only.

Define and use the moment of a force and the torque of a couple.

Show an understanding that, when there is no resultant force and no resultant torque, a system is in equilibrium.

Apply the principle of moments to new situations or to solve related problems.

* Not in H1 syllabus