Forces (OCR)

What are the techniques for measuring short, straight distances?

Using a ruler or tape measure.

What device is suitable for measuring longer distances like a school corridor?

Trundle wheel.

Which device is used for accurate distance measurements indoors?

Ultrasonic sensor or laser rangefinder.

How is time typically measured in experiments?

Using a stopwatch or light gates.

What does a straight line represent in a distance-time graph?

Constant speed.

How do you convert km/h to m/s?

Divide by 3.6.

What does distance represent in physics?

Total path travelled (scalar quantity).

What does displacement represent?

Shortest straight-line path from start to end (vector quantity).

How is velocity different from speed?

Velocity includes direction, while speed does not.

What does the gradient of a velocity-time graph represent?

Acceleration.

In Newton's First Law, what happens to an object without a resultant force?

It remains at rest or moves at constant velocity.

What is Newton's Third Law?

For every action, there is an equal and opposite reaction.

How is force represented in a free body diagram?

As vectors showing direction and magnitude.

What happens to an object accelerating due to unbalanced forces?

It changes speed and/or direction.

What does a flat line in a distance-time graph indicate?

The object is stationary.

What is the formula for Newton’s Second Law?

F = ma, where F is force, m is mass, and a is acceleration.

What is the principle of moments?

For a system to be balanced, moments on both sides must be equal.

What is the measure of gravitational field strength on Earth?

Approximately 9.8 m/s².

How does air resistance affect a skydiver?

It increases until it equals the weight, leading to terminal velocity.

What defines elastic deformation?

The object returns to its original shape when the force is removed.

What occurs during plastic deformation?

The object does not return to its original shape after the force is removed.

What does Hooke’s Law state about springs?

The extension is proportional to the force applied within the limit of proportionality.

What does a moment depend on?

The force applied and the distance from the pivot point.

How do gears affect force and speed?

Smaller gears increase speed but reduce force, while larger gears increase force but reduce speed.

What is the formula for pressure in fluids?

Pressure = Force / Area.

What principle do hydraulic systems operate on?

Pascal’s principle.

How does velocity change during circular motion?

The speed may be constant, but the direction is changing.

What does the area under a velocity-time graph represent?

Distance travelled.

How can average speed for non-uniform motion be calculated?

Total distance divided by total time.

What happens to an object in free fall?

It accelerates downward at approximately 9.8 m/s².