Newton's 1st Law
What is Newton's 1st law?
An object at rest stays at rest, while an object in motion stays in motion, unless acted on by an outside force
What is Newton's 2nd Law?
Force equals mass times acceleration
What is Newton's 3rd Law?
Every action has an equal and opposite reaction
The energy something has due to its motion (moving energy)
Kinetic energy
Why can you slide easily on ice but not on concrete?
Concrete has more friction than ice
These types of forces cause a change in motion
Unbalanced forces
A change in motion (start, stop, speed up, slow down, or change direction)
This is the force that pulls everything towards the center of the Earth
Gravity
How much stuff an object has
Mass
As a car goes down a hill its potential energy ____ and its kinetic energy ____
potential energy decreases and kinetic energy increases
Newton's 1st law is also called the Law of....
Inertia
A 3kg ball is accelerating at a rate of 6 m/s^2. What is its force? (Make sure you include your unit!)
18 N
Gravity is pulling you down towards the ground as you sit at your desk. Why aren't you falling to the floor?
The desk is pushing you up with the same amount of force as gravity
The rate an object moves per unit of distance
List all 4 forces acting on a soccer ball when you kick it
Gravity, the ground pushing up against the ball, the force of your foot, rolling friction/air resistance
Because of Newton's 1st law, if Mrs. Jones slams her car brakes and IS wearing a seatbelt, this will happen
Her body will keep moving forward, but the seatbelt will pull her back
Mrs. Walley pushes a toy car that weighs 7kg and another toy car that weighs 14kg with 28 N of force. Which car will go farther?
Bonus points: How much will each car accelerate?
The 7kg car will go farther
7kg car will accelerate at 4 m/s^2
14kg car will accelerate at 2 m/2^2
a = F/m
Mrs. Hebert is trying to move a refrigerator. She pushes with 25 N of force and the fridge does not move. How mush force is the fridge pushing back on her? These forces are....
25 N
Balanced
Forces acting on an object that are equal in size and opposite in direction
Balanced forces
Coach Powe and JB are playing tug-of-war. Coach Powe pulls to the right with 7N of force. JB pulls to the left with 9N of force. Who wins and what is the net force?
JB wins and the net force is 2N
Coach A has 3 bags of gym equipment. The blue bag has a mass of 12kg. The red bag has a mass of 17kg. The green bag has a mass of 14kg. Which bag will require the least energy to carry?
The blue bag
Mrs Turner and Dr Lyons decide to jog every morning for 1 hour. Mrs Turner jogs at 4mph and Dr Lyons jogs at 5mph. Who goes farther on their morning jog?
Dr Lyons
Mrs. Bonner is trying to move her couch. She is pushing with 17N of force. The force of friction to move the couch is 23N. Her husband comes to help her. How much force does he have to apply in order for them to overcome the friction and make the couch move?
More than 6N
The tendency of an object to resist a change in motion
Inertia
Plastic, carpet, or glass
Carpet because it will have the most friction