When objects collide
True or false - Gravity is a contact force
False
True or false - A collision between air particles differs from a collision between cars because it is not very noticeable and doesn’t make a sound, but it is still considered a collision
True
True or false - Rough surfaces have less friction that smooth surfaces
False
What is friction with air called?
Air resistance or drag
What is motion?
A change in position
What is a force?
A push or pull
A car is traveling 30 km/h east. Suddenly it changes direction and travels north. Is this acceleration?
Yes, it is acceleration. Any change in velocity is acceleration.
What is acceleration?
Change in velocity
In an elastic collision, objects _________ away from each other
bounce
In an inelastic collision objects ________ to each other.
Mr. Phillip pushes an object east with 50N of force. Mr. Robert pushes the same object west with a force of 15N. What is the net force?
35N east
What is Newton's first law also called?
What does it mean?
Law of inertia
An object at rest remains at rest and an object in motion remains in motion unless acted upon by an unbalanced force
Modern cars are designed to have the metal bend on impact. Does this make a car crash an ELASTIC or INELASTIC collision?
Inelastic
If I throw an egg at the wall, what kind of collision will happen?
Inelastic
Which surface would have the least friction?
Ice rink
According to the third law of motion, if I sit down on a chair providing force downwards, what does the chair do back to me?
The chair pushes upwards with the same amount of force.
Car A and Car B are both moving east. Car A has a velocity of 40m/s to the east. While Car B has a velocity of 30m/s east. Car A hits Car B in an elastic collision and bounces with a reduced velocity of 20 m/s to the east. How much is Car B’s velocity?
50m/s east
Object A is traveling east at 20 m/s. Object B is moving at 10 m/s east. They collide inelastically. Object A now has a velocity of 15 m/s. What is the velocity of object B?
15 m/s
What is friction?
A force exerted by surfaces on each other when they are in contact
Describe the relationship between mass and acceleration, which law of motion is this relationship?
More mass = less acceleration
Newton's 2nd law (F=Ma)