Chapter 6

Question 1

What is momentum and it’s direction?

What’s its relationship to kinetic energy?

Answer 1

Direction is same as direction or objects velocity
p=mv
KE=1/2mv^2=p^2/2m

Question 2

How is net force related to momentum and time?

Answer 2

Fnet= Δp/Δt

Question 3

What is impulse?

Answer 3

I=FΔt
I=Δp= mvf-mvi
FavΔt=p

Impulse is the area under the force vs time curve
Oct 12 slide 37

Question 4

What happens when a collision occurs in an isolated system?

Answer 4

The total momentum of the system doesn’t change
Total momentum is conserved
Slide 27 Oct 15

Question 5

What is the long equation for the conservation of momentum?

Answer 5

F21Δt=-F12Δt (Newton’s third law)

m1vf1-m1vi1=-(m2v2f-m2vi2)
Or
m1vf1+m2vf2=m1v1i+m2vi2
Total momentum after the collision is the same as the total momentum before the collision

Question 6

What does it mean for momentum if no external force is acting on a system?

Answer 6

Momentum of system is conserved

Magnitude and direction of total momentum is the same before and after an internal reaction

Question 7

Is total kinetic energy conserved in a collision?

Answer 7

No

It is converted to internal energy, sound energy and work

Question 8

What is a perfectly inelastic collision?

What about elastic collision?

Answer 8

Inelastic- If two colliding object stick together after the collision, momentum is conserved but energy is not
Slide 32 oct 15
Elastic- After collision both object velocities change but both energy and momentum are conserved

Question 9

What are the equations for an isolated, two body collision?

Answer 9

m1v1ix+m2v2ix=m1v1fx+m2v2fx

m1v1iy+m2v2iy=m1v1fy+m2v2fy

Question 10

Do examples on slide 20-21 Oct 17

Answer 10

Okay

Question 11

If a collision is elastic, what is another equation we can write using conservation of energy?

Answer 11

1/2m1v1i^2=1/2m1v1f^2+1/2m2v2f^2