Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.
-
Upload
kerry-hill -
Category
Documents
-
view
218 -
download
1
Transcript of Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.
![Page 1: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/1.jpg)
1
MomentumChapter 7
Page 86 - 99
![Page 2: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/2.jpg)
2
Mass in motionInertia in motionIt is a vector quantity
Definition of Momentum
![Page 3: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/3.jpg)
3
Mass ( kg)Velocity (m/s)
Factors that affect Momentum
![Page 4: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/4.jpg)
4
p = mvp = momentum (kg∙m/s)m = mass (kg)v = velocity (m/s)mass and velocity are directly related to momentum
Equation for Momentum
![Page 5: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/5.jpg)
5
7) m = 40. kg v = 2.5 m/sa. p = mv = (40. kg) (2.5 m/s) =
100 kg∙m/s = 1.0 x 102 kg∙m/s
b. P = mv = (80. kg) (2.5 m/s) = 200 kg∙m/s = 2.0 x 102 kg∙m/s
Problems
![Page 6: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/6.jpg)
6
8) m = 3.5 kg v = 1.5 m/sa. p = mv = (3.5 kg) (1.5 m/s) =
5.3 kg∙m/sb. p = mv = (3.5 kg) (0.75 m/s)
= 2.7 kg∙m/s
Problems
![Page 7: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/7.jpg)
7
9) All momenta are the same.a. p = mv = (60. kg) (4.0 m/s) = 240
kg∙m/sb. p = mv 240 kg∙m/s = (55 kg) v
v = (240 kg∙m/s) / (55 kg) = 4.4 m/sc. p = mv 240 kg∙m/s = m (2.0 m/s)
m = (240 kg∙m/s) / (2.0 m/s) = 120 kg
Problems
![Page 8: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/8.jpg)
8
The mosquito because it has a velocity. If the velocity is zero (tractor trailer), the momentum will be zero.
Which would have a greater momentum, a flying mosquito or a parked tractor trailer? Why?
![Page 9: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/9.jpg)
9
Yes, if the elephant’s velocity is much less than the cheetah or if the elephant is not moving at all.
Is it possible for a 60 kg cheetah to have a greater momentum than a 2300 kg elephant? Explain.
![Page 10: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/10.jpg)
10
Momentum & Impulse Connection
![Page 11: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/11.jpg)
11
The amount of force applied at a certain amount of time.
Impulse is applied in the opposite direction of the motion to slow/stop an object
Impulse is applied in the same direction of the motion
Impulse
![Page 12: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/12.jpg)
12
I = ∆p I = impulse (N∙s)∆p = change in momentum (kg∙m/s)
Ft = m∆vF = force (N) t = time (s)∆v = change in velocity (m/s)
Impulse – Change in Momentum Theorem
![Page 13: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/13.jpg)
13
In a collision, an object experiences a force for a specific amount of time that results in a change in momentum
Impulse – Change in Momentum Theorem
![Page 14: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/14.jpg)
14
A tennis racket is moving east to apply an impulse of 120 N∙s on a tennis ball that is moving west. What would be the change in momentum of the tennis ball?
120 kg∙m/s east
Impulse – Change in Momentum Theorem
![Page 15: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/15.jpg)
15
The velocity change is greatest in case B. The velocity changes from +30 m/s to -28 m/s. This is a change of 58 m/s (-) and is greater than in case A (-15 m/s).
A. Why does case B have a greater change in velocity?
![Page 16: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/16.jpg)
16
Change in momentum depends on change in velocity. Case B has a greater change in velocity.
B. Why does case B have a greater momentum change?
![Page 17: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/17.jpg)
17
Because B has a greater change in velocity.
C. Why does case B have a greater acceleration?
![Page 18: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/18.jpg)
18
Impulse is equal to the change in momentum. Case B has a greater change in momentum.
D. Why does case B have a greater impulse?
![Page 19: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/19.jpg)
19
a. I = Ft = (50. N)(2.5 s) = 130 N∙sb. I = Ft = (25 N)(0.75 s) = 19 N∙s
I = ∆p = 19 kg∙m/s
19) Problems
![Page 20: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/20.jpg)
20
c. ∆p = m∆v = (15 kg) (-10. m/s) = -150 kg∙m/s ∆p = I = -150 N∙s
I = Ft -150 N∙s = F (3.2 s) F = -150 N∙s / 3.2s = -47 N
19) Problems
![Page 21: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/21.jpg)
21
d. I = Ft = (200. N)(12 s) = 2400 N∙s = ∆p = 2400 kg∙m/s
∆p = m∆v 2400 kg∙m/s = (25 kg) ∆v ∆v = (2400 kg∙m/s)/(25 kg) = 96 m/s
19) Problems
![Page 22: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/22.jpg)
22
21) When you increase the time of collision, you decrease the force of collision.
22) The airbag increases the time of collision resulting in the decrease of the force of collision.
23) When you bend your knees, you increase the time of impact which decreases the force of impact.
Ft = m∆v
![Page 23: Chapter 7 Page 86 - 99 1. Mass in motion Inertia in motion It is a vector quantity 2.](https://reader036.fdocuments.in/reader036/viewer/2022062320/56649d025503460f949d5aca/html5/thumbnails/23.jpg)
23
24) Rebounding is when colliding objects bounce off each other.
25) The change in velocity is greater when a car rebounds compared to it crumpling upon impact.It is more beneficial for the car to crumple because less change in velocity means less change in momentum, which means less impulse on the car.
Ft = m∆v