Physics Chapter 7 Study Guide

Front 1

define momentum

Back 1

momentum is inertia in motion, and the product of mass and the velocity of an object

Front 2

How is momentum related to inertia?

Back 2

momentum is inertia in motion, large mass means more momentum

Front 3

how can you increase momentum?

Back 3

by increasing the mass and or the velocity of an object in motion

Front 4

to change momentum, there has to be a change in what?

Back 4

velocity and or mass

Front 5

what does force have to do with momentum?

Back 5

a force is needed to change the mass and or the velocity of a moving object, which then increases or decreases the momentum of an object

Front 6

what is the formula for momentum?

Back 6

p=mv

Front 7

what are the units for momentum?

Back 7

kg(m/s)

Front 8

what is the formula for impulse?

Back 8

impulse=force change in time or ft=change in momentum

Front 9

what are the units for impulse?

Back 9

impulse= newtons x time. im=nxs

Front 10

what is the formula for change in momentum?

Back 10

impulse=force x change in time

Front 11

Compare and Contrast: Increasing and Decreasing momentum. (cannot say one goes up and the other goesdown or anything related to up or down).

Back 11

to achieve both you must apply a force, forincreasing apply force for a longer time with a short impact, for decrease applying a force and increasing the impact time will decrease the momentum. It ishard to change the mass of an object while it is in motion.

Front 12

Why do I want to have “soft” hands when catchinga water balloon?

Back 12

Because the longer impact time between your handand the water balloon, the more the momentum will decrease because when theimpact time is increased the momentum is decreased.

Front 13

Why do I need to increase the time that force isapplied when increasing momentum? Decreasing momentum

Back 13

Because the more force that is applied for the longer time, the more the momentum will increase. The longer period that the force is applied the easier it is to change the mass and velocity.

Front 14

how is bouncing an action-reaction pair?

Back 14

the actions the object hitting the ground, impact, and the impulse is the object bouncing back up again.

Front 15

why does it take more energy to bounce something than it does to stop it?

Back 15

it takes more energy because you must apply enough force to get the object back up once it hits the ground and bounces.

Front 16

why is momentum a vector?

Back 16

because it has magnitude and direction

Front 17

complete the statement- '' if no net force or net impulse acts on a system....''

Back 17

the momentum of that system can not change

Front 18

What happens if the force is internal to thesystem in Conservation of Momentum? Whatif the force is external to the system?

Back 18

If it is internal, then the force pairs will cancel each other and no change will happen. If it is an external system, then change in motion can happen.

Front 19

State the Law of Conservation of Momentum.

Back 19

In the absence of an external force, the momentum of a system remains unchanged.

Front 20

Obtain a Newton’s Cradle from the teacher. What happens when you raise and release 1ball? 2 balls? 3 balls? What happens if you change the height ofrelease?

Back 20

The amount of balls that you release on oneside, the same number will bounce up on the other side. If you increase the drop height then the height that they bounce back up on the other side will also increase to the same height.

Front 21

What has to happen to have a perfectly elasticcollision?

Back 21

the sum ofthe momentum vectors is the same before and after the collision.

Front 22

Why are collisions also an example ofConservation of Momentum?

Back 22

They are examples because whenever objects collide in the absence of an external force, the net momentum of each object before the collision is equal to the net momentum after the collision.

Front 23

How does friction play a part in a collision?

Back 23

Friction helps the objects that are in the collision slow done by rubbing together.

Front 24

Compare and contrast: elastic and inelasticcollisions.

Back 24

When objects collide without being permanentlydeformed and without generating heat, the collision is said to be an elastic collision and the sum of the momentum vectors is the same before and after the collision. When an object collides and generates heat and tangles together it is an inelastic collision.

Front 25

Perfectly elastic collisions do not happen ineveryday life, but they do exist in ____________.

Back 25

the microscopic level

Front 26

Is momentum conserved if the objects do not movein a straight line? Why?

Back 26

yes, because

Front 27

When would you use the formula √2(mv)?

Back 27

we would use it when the momentum of the objectsin the collision is equal in magnitude, after combining.

Front 28

How do you calculate a resultant that is not asquare?

Back 28

you would use the vector rules to equal the original momentum of the objects.

Front 29

When you calculate momentum, you have to includeforce. Yes or No? Why?

Back 29

????

Front 30

Which formula for Conservation of Momentum showsan inelastic collision?

a. m1v1 + m2v2 = (m1+ m2) v

b. m1v1 + m2v2 = m1v1 + m2v2

Back 30

a.