Force Basics
What is a force?
A push or a pull.
What force pulls objects towards Earth?
Gravity.
What do we call a change in an object's position?
Motion
Which surface usually creates more friction: carpet or smooth tiles?
Carpet
What happens when two north poles of magnets are brought together?
They repel each other.
Name two ways a force can change an object.
Change its speed, direction or shape, or make it start or stop moving. Any two.
What force acts when two surfaces rub together?
Friction
What happens when you kick a stationary soccer ball?
The ball starts moving because a force acts on it.
Is friction always a bad thing? Give one example of when it is useful.
No. For example, friction between shoes and the ground helps us walk without slipping.
What happens when the north pole of one magnet is brought near the south pole of another?
They attract each other.
What unit is used to measure force?
Newtons (N).
Name one contact force and one non-contact force.
Contact: friction or air resistance. Non-contact: gravity or magnetism.
A moving bicycle slows down when the rider applies the brakes. What happens to its motion?
Its speed decreases.
What force helps a parachute slow a skydiver down?
Air resistance.
A book rests on a table. Name the two main forces acting on it
Gravity acts downwards, and the table's support force acts upwards.
A student pushes a wall, but it does not move. Is a force still being applied?
Yes. The student is applying a force even though the wall does not move.
Is gravity a contact or non-contact force?
Non-contact force.
A ball rolls towards a wall and bounces back. What has changed about its motion?
Its direction has changed.
Why is it generally easier to slide a box across a smooth floor than across a rough carpet?
The smooth floor usually creates less friction.
Two students pull a rope in opposite directions. Each pulls with 30 N. What is the net force?
0 N. The forces are balanced.
Two students push a box to the right with 10 N each. What is their combined force?
20 N to the right.
A magnet attracts a paper clip without touching it. What type of force is acting? Explain.
Magnetic force; it is a non-contact force because the objects do not need to touch.
A toy car is pushed harder than before on the same surface. Predict how its motion might change.
It may accelerate more or reach a greater speed, assuming other conditions remain the same.
A cyclist stops pedalling but continues moving before gradually slowing down. Explain why.
The bicycle continues moving due to its existing motion. Friction and air resistance oppose its motion, causing it to slow down.
A box is pushed right with 50 N while friction acts left with 20 N. Calculate the net force and state its direction.
50 - 20 = 30N to the right.