First Law and a little 2nd
What is Newton's First Law?
Law of Inertia
- an object in motion tends to stay in motion and an object at rest tends to stay at rest unless acted upon by an unbalanced force
What is Newton's Second Law?
Force = Mass x Acceleration
What is Newton's Third Law?
Every action has an equal and opposite reaction.
What is force measured in? (units)
Newtons (N)
If the mass is 100 kg and the acceleration is 2.5 m/s2, what is the force?
250 N
If I increase the mass of an object, what happens to acceleration?
decrease
a = F/m
If a ball is pushed with a force of 12 N to the left and 12 N to the right by another person, what type of forces are acting on the object in the diagram? What will happen to the ball?
balanced forces, so the ball will not move
What is mass measured in? (units)
kilograms (kg)
A net force of 18 N acts on a ball with a mass of 3 kg. According to Newton’s second law, what is the acceleration of the ball? Be sure to include units.
a = F/m; a = 18 N/3 kg, so a = 6 m/s2
If I increase the force on an object, what happens to acceleration?
increase
If I know the Force and acceleration, how would I solve for mass?
m = F/a
If box is being lifted into the air with a force of 50 Newtons, but someone is pulling down on the box with a force of 20 Newtons, what is the net force on the box? Which direction will it go?
force of 30 Newtons; it will go up
What is acceleration measured in? (units)
m/s2
Velocity is determined by ______ and ______.
Speed is calculated by _____ over ______.
speed and direction
distance over time
If I am pulling a cart to the right with a force of 55 Newtons while my friend pushes the cart with me with a force of 80 Newtons, what is the net force on the cart?
135 Newtons
Force is ______ proportional to acceleration.
Mass is _____ proportional to acceleration.
directly, inversely
If a rolling cart weighs 12 kg, the child riding on the rolling cart weighs 24 kg, and the force pushing the cart was 72 Newtons, what is the acceleration in m/s2?
2 m/s2
If a box is being pushed with a force of 13 Newtons to the right and at the same time, it is being pushed with a force of 25 Newtons to the left, which direction will it go and with how much net force?
It will go to the left with a force of 12 N.
If I am pushing a box to the right with a force of 15 Newtons and my friend is pulling the box in the same direction with a force of 30 Newtons, which direction and with how much net force will the box go?
The box will go to the right with a force of 45 Newtons.
During a football game, Camila and Ronak watch a professional quarterback throw a football to a teammate. The football has a mass of 0.40 kg. In order for the football to reach his teammate, he must throw it with a force of 11 N. This force would allow the ball to move toward his teammate at the most effective rate for the teammate to score points. Camila and Ronak decide they want to try to recreate the play in her own youth football game the next weekend. During the game, she is able throw a football with a mass of 0.35 kg with a force of 7 N.
How would decreasing the mass of the football to 0.30 kg affect its acceleration?
Firstly, decreasing mass would increase acceleration. The calculation would be a = F/m; a = 7N/0.35 kg, so a = 20 m/s2
Maria and Pablo are skateboarding at a skatepark. Maria has a mass of 60 kg and skates forward with a force of 10 N. Pablo has a mass of 70 kg and skates forward with the same force. Which skater has a higher acceleration? Calculate the value for double the points.
Maria has higher acceleration because she is lighter. The acceleration is 0.17 m/s2
One of the most popular rides at an amusement park is the drop tower. The drop tower carries passengers anywhere from 30 ft to 430 ft into the air before releasing the passenger vehicle and allowing it to free-fall. Read each scenario.
The passenger vehicle and gravity exert equal and opposite forces before gravity is overcome as the vehicle travels into the air.
The passenger vehicle stays at the bottom of the tower until pulled upwards by the ride engine.
The greater the mass of the passenger vehicle, the faster it will fall.
Which option matches each of Newton’s Laws with the scenario as it occurs on a drop tower at an amusement park?
Newton’s First Law: 2; Newton’s Second Law: 3; Newton’s Third Law: 1
A kid straps an action figure into a toy car and pushes it down a ramp. At the end of the ramp, the toy car hits a wall, bounces off, and comes to a stop. The restraints keep the action figure from falling out of the toy car. Describe how each of Newton's 3 laws shows up in this system.
1. The car's inertia did not want the car to stop until the unbalanced force (wall) acted on it.
2. The more force the car was pushed with, the more acceleration it had.
3. The action-reaction was when the car and the wall collided and the car bounced back in the opposite direction.
If I am pushing a box to the left with a force of 4 Newtons, my friend is helping push the box with a force of 8 Newtons with me, but our other friend is pushing against us with a force of 6 Newtons, which direction is the box going to go and with how much force?
The box will go to the left with a force of 6 Newtons.