Newton's Laws
A car crashes into a solid wall during a test. Compare the force on the wall with the force on the car using Newton’s Third Law.
The car pushes on the wall is exactly the same strength but in the opposite direction as the force the wall pushes back on the car, meaning the forces are equal and opposite action-reaction pairs, even though the car changes speed drastically and the wall doesn't move much because the wall is so massive.
Explain why gravitational forces are "always attractive" and give a real-world example
Gravity is attractive because mass pulls masses toward each other; example: Earth pulling an apple downward
What three things are required when describing an object's position?
Reference Point
Direction
Distance
If you push a crate with 10 N to the right and a friend pushes with 25 N to the left, what is the net force (magnitude and direction)?
15 N to the left
True or False
The acceleration of an object is always in the direction of the net force acting on it.
True
Describe Newton’s First Law in one sentence (100 points) and give a classroom example (100 points)
An object in motion will stay at motion unless acted upon by an outside force. An object at rest will stay at rest unless acted upon by an outside force.
Examples:
soccer ball on a field
A ball rolling
True or False
Compared to the force of the book on the desk, the force of the desk on the book is the same
True
A swimming student goes 20 m in 40 s. Calculate the swimmer’s average speed in m/s
Average Speed = Distance/Time
20m/40s = 0.5m/s
During bowling: select all correct statements (use evidence from forces and motion):
a. The ball is accelerated while pushed by the student’s hand due to an unbalanced force.
b. The ball slows down as it rolls because friction exerts an unbalanced force.
c. The ball is accelerated while held in the student's hand due to balanced forces.
d. The ball does not change its motion as it rolls because of the balanced force provided by friction.
e. The ball does not change its motion while it is held in the student’s hand due to balanced forces.
A, B, and E.
What is a force?
A push or a pull.
State Newton’s Second Law as an equation and explain what each symbol means. Note: write the equation using the correct mathematical format.
F = MA
Force equals Mass times Acceleration
Which statement is NOT true about gravitational force: it is a noncontact force, it depends on mass, it depends on speed, or it depends on distance?
Explain your choice.
Speed
The force of gravity between two objects depends solely on their masses and the distance between them, not their speed.
A person walks 20 m north, 10 m south, and 3 m north. To have a displacement of 0 m, how many meters and in which direction must the person walk?
13 m South
SURPRISE! Are you going to chance it? You may receive more points or lose!
Oh no! - 300 points
What can be changed when describing motion? It is just the chosen starting point.
Reference Point
Explain Newton’s Third Law (200 points) and give an example involving two students pushing off each other while sitting on rolling chairs (200 points)
For every action there is an equal and opposite reaction.
In the rolling chair example, Student 1 pushes Student 2 (action), and simultaneously, Student 2 pushes Student 1 with the exact same force back, causing both students (and their chairs) to roll away from each other.
Two people pull on a chain with 500 N and 600 N in opposite directions. What is the Net Force? Provide the letter and a one-sentence explanation.
100 N
600 - 500 = 100
List two reasonable reference points you could use to describe someone walking on a moving bus.
Interior of the bus
Ground outside of the bus
A cart attached to a string over a pulley is pulled by a hanging mass. Identify the independent and dependent variables for an experiment where students add different weights to the hanger and observe cart motion. Then describe two forces acting on the cart and their directions.
Independent - (What is changed): The weight of the hanging mass
Dependent- (What is observed/measured): The acceleration of the cart
Which law states that for any interaction, the force exerted by the first object on the second is equal in strength and opposite in direction to the force exerted by the second on the first?
Newton's Third Law of Motion
Describe all three of Newton’s laws in a table: Law (name), definition (one sentence), and a clear real-world example (one sentence each)
First Law - An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. Example: soccer ball
Second Law - F = MA. Example: pushing a full shopping cart
Third Law - For every action, there is an equal and opposite reaction. Example: When you push off a wall to jump, the wall pushes back on you with the same force, propelling you away.
Eve hypothesizes that the heavier shopping cart applied more force to the lighter cart than vice versa. Do you agree or disagree? Use Newton's third law to explain your reasoning in 2–3 sentences.
Newton's Second Law of Motion
F = MA
The force that opposes motion
Friction
Make a claim about the forces on the cart when the cart does not move in the pulley experiment. Support the claim using Newton’s laws (include a short explanation referencing balanced forces and net force)
When a cart in a pulley experiment is not moving, the horizontal forces acting on it—specifically the tension force from the string and any opposing friction—are perfectly balanced, resulting in a net force of zero.
Knowing an object’s position requires you to also know what?
Reference Point