Force
True or False: A force is a push, pull, or twist
True
How many laws of motion are there?
3
What is another name for Newton’s First Law?
Inertia
What does the formula F = ma stand for?
Force = mass x acceleration
State Newton’s Third Law of Motion.
For every action, there is an equal and opposite reaction.
Newton (N)
Which law explains why you wear a seatbelt?
Newton’s First Law (inertia).
According to the First Law, what must act on an object to change its motion?
If you push a light box and a heavy box with the same force, which one accelerates more?
The lighter box
When you jump off a boat, why does the boat move backward?
Your push forward on the boat makes the boat push back on you, moving it backward.
If an object is not moving, what can we say about the forces acting on it?
They are balanced (net force = 0).
Which law explains why pushing a shopping trolley gets harder as it’s filled?
Newton’s Second Law (more mass → less acceleration for same force).
Why does a soccer ball eventually stop rolling on the grass?
What is the net force if a 4kg ball accelerates as 5m/s/s?
20N
If a swimmer pushes water backward with their hands, what happens to their body?
The water pushes their body forwards.
What instrument is used to measure force?
A spring balance (or force meter).
Why does a balloon fly around the room when the air rushes out?
Newton’s Third Law – air pushes back, balloon moves forward.
In space, why would a ball keep moving forever once kicked? An object with a lot of inertia is likely to do what
There is no air resistance or friction to stop it
A 2 kg ball is pushed with a force of 10 N. What is its acceleration?
5 m/s/s
A rocket launches upward because gases are pushed downward. Explain this in terms of action and reaction.
Action: Rocket pushes gases down. Reaction: Gases push rocket up.
Explain the difference between contact forces and non-contact forces, giving one example of each.
Contact forces act when objects touch (e.g., friction, tension). Non-contact forces act at a distance (e.g., gravity, magnetism).
Explain how Newton’s 3 Laws apply when a soccer player kicks a ball.
1st: Ball stays still until kicked; 2nd: Kick force causes acceleration; 3rd: Ball pushes back on foot.
A passenger not wearing a seatbelt continues moving forward when a car stops suddenly. Explain this using Newton’s First Law.
The passenger’s body wants to keep moving at the same speed and direction (inertia) until a force (seatbelt/dashboard) acts on them.
A car accelerates at 5 m/s² with a force of 10,000 N. What is the car’s mass?
2000kg
.
Why doesn’t Earth noticeably move when you jump, even though you push down on it?
Because the Earth’s mass is so large