Effects of forces Flashcards – Cambridge IGCSE (9–1) Physics 0972 (Extended) (2026–2028)

How can a force deform an object?

By changing its size or shape.

When does an elastic solid return to its original shape and size after the deforming force is removed?

When it has not been deformed beyond its elastic limit.

What is extension?

The increase in length from the original, unloaded length.

What does a load–extension graph show?

How extension changes as the applied load changes.

How can you obtain and plot data for a load–extension graph?

1. Suspend the solid securely and measure its original length.
2. Add known loads, measuring the length after each addition.
3. Subtract the original length to find each extension.
4. Plot the paired loads and extensions with labelled axes and units.

What does a straight-line section through the origin on a load–extension graph show?

Extension is proportional to load over that range.

What can measurements during unloading reveal about a solid?

Whether it returns to its original length.

What is the resultant force on an object?

The single force with the same combined effect as all the forces acting on the object.

How do you calculate the resultant of forces along the same straight line?

Choose one direction as positive and the opposite direction as negative, then add the signed forces.

What does a zero resultant force mean for forces along a straight line?

The forces balance along that line.

How does an object move when the resultant force on it is zero?

If at rest, it remains at rest. If moving, it continues in a straight line at constant speed.

What effect does a non-zero resultant force have on an object's velocity?

It changes the object's velocity.

In what ways can an object's velocity change?

Its speed can increase or decrease, its direction can change, or both can change. A direction change alters velocity even at constant speed.

What is solid friction?

A force between two surfaces in contact that opposes their relative motion or tendency to move relative to each other.

What thermal effect can solid friction produce?

Heating at the contacting surfaces.

What is fluid drag?

A frictional force acting on an object moving through a fluid, such as a liquid or gas.

In what direction does drag act on an object?

Against the object's motion relative to the surrounding fluid.

What is air resistance?

Drag acting on an object moving through air.