Chapter 12 Test Flashcards
What is freefall
An object accelerating downwards without outside force pushing upward, second law unbalanced
What is terminal velocity
The speed at which an object no longer accelerates, first law balanced forces
What is projectile, and what is its motion
Any object thrown in the air, always a curved path
What is Newton’s first law
Object at rest remains and rest and an object in motion remains in motion until acted on by an unbalanced force
Newtons first law describes motion as
Balanced forces acting on an object
What is newtons second law
And unbalanced force on an object that causes it to accelerate in the direction of that force
Newtons first law is also known as
Inertia
What is newtons third law
For every action by a force there is always an equal and opposite reaction by another force
What is force
A push or pull that stops starts or changes direction of an object in motion
What is friction
A force that opposes the motion of an object
What is sliding friction,example
Went to solid forces slide over each other, skiing
What is rolling friction, example
When an object rolls over a surface, skateboarding
What is fluid friction, example
When an object moves through a fluid liquid or a gas, skydiving or swimming
What is static friction, example
A force that acts against objects that are not moving. Strong friction., Pushing a desk or walking
What is momentum
Mass in motion, moving body that equals the product of its mass multiplied by its velocity
What is the law of conservation of momentum
Total momentum remains the same. If one object loses momentum another object is gaining momentum
How is the 90 kg defensive back able to knock over a 120 kg fullback
The defensive back has a greater velocity which gives them more momentum
Why is a follow-through important and tennis and baseball
Longer in contact, more momentum is transferred to the ball
What is gravity
The attractive force between all objects in the universe
What are three things force can you do to an object
Stop start or change direction
What are three factors that affect the force of sliding friction
Surface area, texture, Mass.
What are three examples of things that are used to increase friction to help us
Wheels, shoes, sails on boats
What are balanced forces give some examples
Terminal velocity, constant velocity
What effect do balanced forces have on objects motion
None, they don’t change the motion
Which law deals with conservation
Third law, balanced
Car a and Car b are both traveling at 100 km per hour and collide had on. Car b is pushed back 50 km why?
Car a has to be twice as heavy
What do we call the change in momentum?
impulse
How is force related to time
More time equals less force and vice versa
What are unbalanced forces
Second law, forces that do not add up to zero, changes objects motion
What effect does an unbalanced force have on the speed and direction of an object
Changes speed or direction
What is inertia
The resistance of an object to change motion, first law
If you jumped up in the air neglecting air resistance in the back of a Ford pick up truck going 100 mph, where would you land? why?
In the same place you jumped because your body is still going 100 mph in the air
Which two factors affect the acceleration of an object
Force and mass
What does newtons third law say about forces
They always act in pairs
Give three examples of a newtons third law
Walking, leaning on the wall, shooting a rifle
What is terminal velocity
When acceleration no longer increases, constant velocity, FF equals FG
What causes the curved path of a projectile
Gravity
What is weight
Measure of the force of gravity on an object to
Would your weight be greater on earth, the moon, or Saturn
Saturn
What are your way to be greater in Tempe or in Flagstaff? Why?
Tempe, closer to center of Earth
Would your mass be greater here, or on the moon
Here
What is a synonym for air resistance
Drag force
Projectile motion is the product of gravity and what
Inertia
