Midterm

Question 0

Two skaters, an adult and a child, stand at rest on the ice, so their total momentum is zero. Then they push off each other. What happens s to their momentum so AFTER they push off of each other?

Answer 0

The total momentum of the two skaters is zero because the skaters have the same momentum, but in opposite directions

Question 1

In a set, can a momentum be greater at the end of the experiment then it was at the beginning?

Answer 1

No. Throughout the experiment, the momentum stays the same as it was at the beginning. Only the velocity changes.

Question 2

True or false: the total momentum BEFORE the collision is equal tho the momentum AFTER the collision.

Answer 2

True

Question 3

How do you calculate the total momentum before the event?

Answer 3

M1(v1)+m2(v2)

So add the first mass times the first velocity to the second mass times the second velocity

Question 4

How do you calculate the total momentum after the collision?

Answer 4

M1(v1)f+m2(v2)f=final momentum

Add the first mass x first velocity x force to the second mass x the second velocity x force

Question 5

True or false
If you are changing the impulse of an object form 0 to a higher velocity, the longer you apply the force the greater the impulse, the amd the faster and object goes

Answer 5

True

Question 6

What is conservation?

Answer 6

When the momentum before and after the collision is the same

Question 7

What is explosion?

Answer 7

Objects start together but end apart

Question 8

What are elastic collisions?

Answer 8

Objects start off apart, collide, and don’t stick

They start apart and end apart

Question 9

What are non elastic collisions?

Answer 9

When objects start apart and end together

Question 10

What is the “equation” of conservation of momentum?

Answer 10

P before collision = P after collision

Question 11

What is centripetal force?

Answer 11

The force that keeps am object going in a circle

Question 12

Define period

Answer 12

The time it takes to make an rotation

Question 13

When a car is turning, what provides the centripetal force?

Answer 13

Friction

Question 14

What provides the centripetal force when the earth is orbiting around the sun?

Answer 14

Gravity

Question 15

Does a train going around in a circle at a constant speed have acceleration?

Answer 15

Yes; it is changing direction

Question 16

Does a train going around in a circle at a constant speed change velocity?

Answer 16

Yes; it is changing direction

Question 17

Which direction does the centripetal force always point?

Answer 17

To the middle

Question 18

Which direction is the velocity pointing when an object is moving in a circle?

Answer 18

Perpendicular to the centripetal force

Question 19

Which spool of thread is moving faster, the one on the outside of the record player or the inside?

Answer 19

The spool of thread on the outside; it has a greater distance to cover for the same amount if time.

Question 20

Which spool of thread has a greater period, the one on the outside of the record player or the inside?

Answer 20

They have the same period

Question 21

What factors affect the force of gravity between two objects?

Answer 21

Mass and distance

Question 22

Does mass affect the force of gravity between two objects?

Answer 22

Yes

Question 23

If you double the mass of one object, what happens to the force of gravity between the two objects?

Answer 23

It increases by a fourth

Question 24

If you double the mass of both objects, what happens to the force of gravity between the two objects?

Answer 24

It doubles

Question 25

If you double the distance between two objects what happens to the force of gravity between them?

Answer 25

It decreases by half

Question 26

If you half the distance between two objects, what happens to the force of gravity between them?

Answer 26

It increases by a fourth

Question 27

Why can't you feel the force of gravitational pull between you and an apple?

Answer 27

The mass is too small

Question 28

If you are in space, orbiting the earth, is there a force of gravity on you?

Answer 28

Yes.

Question 29

If you are in space, orbiting the earth, why do you feel weightless

Answer 29

Because there is no Fn acting on you

Question 30

What is Newton's first law?

Answer 30

An object at rest stays at rest unless acted upon by an outside force, and an object in motion continues in a straight line at a constant velocity unless acted upon by outside forces.

Question 31

Of you were in a spaceship, and fired a 15kg cannonball into frictionless space, after you fires the cannonball, how much force would you need to apply to keep it moving?

Answer 31

None, as there is no Ff to slow it down

Question 32

What is the definition of inertia?

Answer 32

An object's resistance to a change of motion

Question 33

A car is moving at a constant velocity. What is the net force acting on it?

Answer 33

0

Question 34

What is miu?

Answer 34

The coefficient of friction

Question 35

What is miu affected by?

Answer 35

Surface texture and weight

Question 36

Is miu affected by surface area?

Answer 36

No

Question 37

What is air resistance?

Answer 37

Friction caused by air

Question 38

What is air resistance NOT affected by?

Answer 38

Weight

Question 39

What is air resistance affected by?

Answer 39

Surface area, aerodynamics, air density, and velocity

Question 40

What is Newton's second law?

Answer 40

Net force= mass x acceleration

Question 41

Compare velocity and acceleration

Answer 41

Velocity is: how fast | Acceleration: how fast velocity CHANGES.

Question 42

Two identical cars are traveling T 25mph. The first cars stops in 1s because it hits the wall. The second car stops in 5s because the driver hit the brakes. Which car has a greater change in momentum?

Answer 42

The change in momentum a are equal, because both start at 25mph, and end at 1.

Question 43

Two identical cars are traveling T 25mph. The first cars stops in 1s because it hits the wall. The second car stops in 5s because the driver hit the brakes. What has a greater impulse, the brakes or the wall?

Answer 43

The impulses are the same

Question 44

When doing problems on universal gravitation, and the question is talking about halving or multiplying the distance, what equation can you use?

Answer 44

(d1/d2) squared