BBC Bitesize KS3 Force diagrams and resultant forces

What does a free body diagram show?

• The color of an object

• The speed of an object

• The forces acting on an object

• The temperature of an object

How should you represent the object in a force diagram?

• As a small box or dot

• As a square

• As a large circle

• As a detailed drawing

What should be used to draw the arrows in a force diagram?

• A pen

• A brush

• A pencil and ruler

• Fingers

In which direction does the normal reaction force point in a free body diagram?

• Parallel to the surface

• At right angles to the surface

• In the direction of motion

• Downwards

How do you calculate the resultant force when forces act in the same direction?

• By subtracting the forces

• By adding the forces together

• By dividing the forces

• By multiplying the forces

What is the resultant force if two forces of 20 N and 10 N act in opposite directions?

• 30 N to the left

• 10 N to the left

• 10 N to the right

• 30 N to the right

What happens if the forces acting on an object are balanced?

• There is no resultant force

• The object accelerates

• The object changes color

• The object vanishes

Describe the motion of a car with equal thrust from the engine and air resistance.

• Travelling at a constant velocity

• Accelerating

• Decelerating

• Spinning

What is the resultant force acting on a box at rest on a table with equal weight and normal reaction force?

• 200 N

• 100 N downwards

• 100 N upwards

• 0 N

What indicates that an object is accelerating?

• Negative forces

• Zero forces

• Balanced forces

• Unbalanced forces