c) Forces, movement, shape momentum

When a force is exerted on an object how can it affect the object?

Change in:

Speed

Direction

Shape

What is a gravitational force?

An attraction between all objects with mass.

How to have a greater gravitational force?

The more massive the object, greater the gravitational force.

What is an electrostatic force?

A force between two objects with a charge.

What are scalar quantities and give examples?

Quantities that have magnitude but no direction.

E.g. mass, speed

What are vector quantities and give exmaples?

Quantities that have both magnitude and direction.

E.g. force, velocity

How to work out resultant force of forces that act along a line?

By adding all forced acting against object.

Define friction?

A force which opposes the motion of an object.

How to work out stopping distance?

Thinking distance + braking distance

Factors that affect thinking distance?

Speed of car

Reaction time of driver

Factors that affect braking distance?

Speed of car

Mass of car

How good brakes are

Weather conditions

What forces do falling objects experience?

Weight

Air resistance

How is a terminal velocity reached?

When the upward and downward forces are balanced.

Constant velocity is reached.

How to investigate how extension varies with applied force for springs and rubber bands?

1. Record initial length of spring/rubber band.

2. Add 100g mass hanger onto spring/rubber band.

3. Record the mass(kg) and position(cm) from ruler.

4. Repeat thus process until all masses have been added.

5. Remove masses and repeat entire process until it’s been carried out 3 times and find average length.

How to investigate how extension varies with applied force for metal wires?

1. Measure original length of the wire using a meter ruler and mark a point with tape.

2. Record initial length of wire to marker.

3. Add a 100g mass onto mass hanger.

4. Record new reading of the tape marker from meter ruler.

5. Repeat process until all masses have been added.

6. Remove masses and repeat whole process three times to find average length.

State hooke’s law and describe how it would look on a force-extension graph?

The extension of an elastic object is directly proportional to the force applied, up to the limit of proportionality.

Straight diagonal line.(linear relationship)

What is elastic behaviour?

The ability of a material to recover its original shape after the forces causing deformation have been removed.