Unbalanced VS Balanced Forces
Two people push a box with equal force in opposite directions. What is the net force?
Newton’s 1st Law is also called the law of ___.
Inertia
Newton’s 2nd Law explains the relationship between force, mass, and ___.
acceleration
Newton’s 3rd Law states that for every action force there is ____.
An equal and opposite reaction force.
Which force pulls objects toward Earth?
Gravity
A soccer ball sitting still on the field is an example of _____. (balanced or unbalanced force)
Balanced Force
Why does a passenger move forward when a car suddenly stops?
The passenger’s body continues moving due to inertia, an object in motion stays in motion unless acted upon by an outside force.
A force of 20 N acts on an object with a mass of 5 kg. What is the acceleration?
Formula: a = F / m
4 m/s²
Why does a swimmer move forward when pushing water backward?
The water pushes the swimmer forward with an equal and opposite force.
What is friction? (BE SPECIFIC)
A force that slows down a sliding object. (resistance)
A car begins speeding up after the driver presses the gas pedal. What does this tell you about the forces acting on the car?
The forces became unbalanced.
A hockey puck slides across ice for a long distance because ____.
There is little friction acting on it.
Which object accelerates MORE when pushed with the same force: an empty cart or a full cart? Why?
The empty cart, because it has less mass and can be put into motion/moved with less force.
A rocket launches upward because ____.
Exhaust gases push downward while the rocket is pushed upward.
A sled is pulled with 30 N forward while friction pulls back with 10 N. What is the net force?
20 N forward
A box is pushed with 15 N to the right and 10 N to the left. What is the net force and direction?
5 N to the right.
A book rests on a table. How can you BEST explain this situation?
Balanced forces keep the book at rest.
Why is it harder to push a refrigerator than a chair?
The refrigerator has greater mass and needs more force to accelerate.
When jumping off a skateboard, why does the skateboard roll backward?
Action-reaction forces act in opposite directions.
How does friction help people walk safely?
Friction provides grip between shoes and the ground.
Explain why an object can still move while forces are balanced.
Balanced forces can allow constant motion if speed and direction do not change.
A student claims objects always need force to keep moving. Is this statement incorrect or correct? Explain your answer.
Objects continue moving unless acted on by an unbalanced force.
A student doubles the force on an object while keeping mass the same. What happens to acceleration?
Acceleration doubles as well.
A student says action and reaction forces cancel each other out completely. Why is this incorrect?
They act on different objects, not the same object.
A truck and a small car collide. Which vehicle experiences the greater force?
Both experience equal force, just in opposite directions.