Force Basics
What is a force?
A push or pull on an object.
What does it mean if forces are balanced?
The net force is 0, and there’s no change in motion.
If 5 N pushes right and 5 N pushes left, what is the net force?
0 N — balanced
You push a shopping cart that starts moving. Which type of force is this?
Unbalanced force
Can an object have forces acting on it but not move? Explain.
Yes, if the forces are balanced.
What two things describe a force?
Strength (magnitude) and direction.
What happens when forces are unbalanced?
The object speeds up, slows down, or changes direction.
If 10 N pushes right and 4 N pushes left, what is the net force and direction?
6 N to the right
Why does a soccer ball eventually stop rolling after being kicked?
Friction and gravity slow it down.
How does friction affect net force?
It resists motion and can reduce the net force.
What unit is force measured in?
Newtons (N)
If an object is moving at a constant speed, are the forces balanced or unbalanced?
Balanced
Two students pull a rope in the same direction: 6 N and 8 N. What’s the net force?
14 N in that direction
A skydiver falling reaches constant speed—what type of forces are acting?
Balanced (gravity = air resistance).
A toy car is pushed with 8 N forward, and the friction is 3 N backward. What’s the net force?
5 N forward.
What tool is used to measure force?
A spring scale.
Give an example of an unbalanced force in action.
A soccer ball being kicked.
A 10 N force pulls left, and a 15 N force pulls right. What’s the net force?
5 N to the right
When you slide a box across the floor, what two forces are acting on it?
Applied force and friction.
Describe a situation where the forces are balanced but the object is still moving.
A car cruising at a constant speed on a straight road.
A skateboarder moves down a ramp faster and faster. Which forces are acting on them, and are they balanced or unbalanced?
Gravity pulls them down the ramp and friction resists motion — the forces are unbalanced, causing acceleration.
Explain why a book resting on a table does not move.
Gravity pulls down, and the table pushes up with equal force — balanced forces.
An object has a net force of 0 N. What can you say about its motion?
It is not accelerating; it stays at rest or moves at constant speed.
A plane takes off from the runway. Describe what forces are acting on it.
Lift, gravity, thrust, and drag.
Three students push a box: two push right with 5 N and 7 N, and one pushes left with 4 N. What is the net force and direction?
8 N to the right (5 + 7 − 4 = 8 N)