5 pt.
5 pt.
5 pt.
5 pt.
5 pt.
10 pt.
10 pt.
10 pt.
10 pt.
10 pt.
15 pt.
15 pt.
15 pt.
15 pt.
15 pt.
20 pt.
20 pt.
20 pt.
20 pt.
20 pt.
25 pt.
25 pt.
25 pt.
25 pt.
25 pt.
1-5
How do you calculate the
momentum of an object?
1-5A
How do you calculate the
momentum of an object?
Momentum = Mass x Velocity
1-10
True or False?
Momentum is a vector quantity.
1-10A
True or False?
Momentum is a vector quantity.
True
1-15
What is the momentum
of a 0.520-kg
object moving at a velocity of 14 m/s?
1-15A
What is the momentum
of a 0.520-kg
object moving at a velocity of 14 m/s?
Momentum = Mass x Velocity
p = mv = (0.520 kg)(14 m/s)
p = 7.28 kg m/s
1-20
Which of the following objects has the
greatest Momentum?
A) a .22-caliber bullet fired from a rifle
B) a bus speeding along a highway
C) a sprinter running the 100-yard dash
D) the Earth in its orbit
E) not enough info to answer
1-20A
Which of the following objects has the
greatest Momentum?
A) a .22-caliber bullet fired from a rifle
B) a bus speeding along a highway
C) a sprinter running the 100-yard dash
D) the Earth in its orbit
E) not enough info to answer
What is the total momentum
of the following
1-25
situation? Assume there is no friction.
2 kg
1.5 m/s
0.8 m/s
3 kg
What is the total momentum
1-25A of the following
situation? Assume there is no friction.
2 kg
1.5 m/s
0.8 m/s
3 kg
Momentum of LH-cart = (2 kg)(1.5 m/s) = + 3 kg m/s
Momentum of RH-cart = (3 kg)(- 0.8 m/s) = - 2.4 kg m /s
Total Momentum = + 3 kg m/s – 2.4 kg m/s
= 0.6 kg m/s
2-5
An impulse is equal to which of the
following?
A)
B)
C)
D)
E)
force times distance
force of impact
change in kinetic energy
change in momentum
none of these
2-5A
An impulse is equal to which of the
following?
A)
B)
C)
D)
E)
force times distance
force of impact
change in kinetic energy
change in momentum
none of these
2-10
If a boxer wishes to reduce the force of
impact from an incoming punch, what
should they do to the time of impact?
2-10A
If a boxer wishes to reduce the force of
impact from an incoming punch, what
should they do to the time of impact?
Increase the time of impact
2-15
What is the change in momentum of a
soccer ball that is kicked with a force
of 75-N over a time of 0.18 seconds?
2-15A
What is the change in momentum of a
soccer ball that is kicked with a force
of 75-N over a time of 0.18 seconds?
Change in momentum = impulse = F t
F t = (75 N)(0.18 s)
F t = 13.5 N s
2-20 are traveling
A Mack truck and bug
towards one another when they collide
head-on. Which one experiences the
greater impulse?
A)
B)
C)
D)
the Mack truck
the bug
they both experience the same impulse
not enough info
A Mack truck and 2-20A
bug are traveling
towards one another when they collide
head-on. Which one experiences the
greater impulse?
A)
B)
C)
D)
the Mack truck
the bug
they both experience the same impulse
not enough info
2-25
A 1,000 kg rocket is launched
from rest to a
speed of 2500 m/s in a time of 2.5 minutes.
What was the average force (in Newtons)
exerted on the rocket?
A 1,000 kg rocket is2-25A
launched from rest to a
speed of 2500 m/s in a time of 2.5 minutes.
What was the average force (in Newtons)
exerted on the rocket?
Change in momentum = Impulse
∆m v = F t ==> F = m (vf – vi) / t
F = (1000 kg)(2500 m/s - 0 m/s )/(150 s)
F = 16,667 N
3-5
True or False?
Momentum is conserved in
all kinds of collisions.
3-5A
True or False?
Momentum is conserved in
all kinds of collisions.
True
3-10
Which kind of collision
conserves
both momentum and kinetic energy?
A)
B)
C)
D)
elastic
inelastic
both
neither
3-10A
Which kind of collision
conserves
both momentum and kinetic energy?
A)
B)
C)
D)
elastic
inelastic
both
neither
3-15
Why is it safer to stop an out-ofcontrol car by running into a pond
versus hitting a concrete wall?
3-15A
Why is it safer to stop an out-ofcontrol car by running into a pond
versus hitting a concrete wall?
By running into the pond, the time it
takes the car to slow down to a stop is
lengthened. Therefore the stopping
force is decreased.
3-20 collision is more
Why is it that a bouncing
damaging than a sticking collision (assuming
the same time of impact in each case)?
3-20A collision is more
Why is it that a bouncing
damaging than a sticking collision (assuming
the same time of impact in each case)?
A bouncing collision is more damaging
because the change in velocity, and
therefore the change in momentum, is
greater. This leads to a larger force.
A 0.25 kg ball is hit by 3-25
a stick - the incoming
velocity of the ball is +25 m/sec and the outgoing
velocity is - 20 m/sec. If the time of contact is
0.078 sec, what was the force of impact?
A 0.25 kg ball is hit by3-25A
a stick - the incoming
velocity of the ball is +25 m/sec and the outgoing
velocity is - 20 m/sec. If the time of contact is
0.078 sec, what was the force of impact?
Impulse = Change in Momentum
F t = m v ==> F = m (vf – vi) / t
F = (0.25 kg)(-20 m/s - 25 m/s)/(0.078 s)
F = -144.2 N
When an asteroid 4-5
collides with the
Moon, the Moon drastically changes
the momentum of the asteroid. By
how much does the Moon change its
momentum?
When an asteroid4-5A
collides with the
Moon, the Moon drastically changes
the momentum of the asteroid. By
how much does the Moon change its
momentum?
Precisely the same amount
4-10
A firecracker is sitting
on the ground when
it is lit. After the explosion, what is the
total momentum of the pieces flying away?
4-10A
A firecracker is sitting
on the ground when
it is lit. After the explosion, what is the
total momentum of the pieces flying away?
Zero!!!
…because the momentum of the firecracker
before the explosion was zero, and
momentum must be conserved.
4-15
A bullet is fired from
a heavy rifle.
Two questions:
Which one experiences a greater
change in momentum?
Which one experiences a greater
change in velocity?
4-15A
A bullet is fired from
a heavy rifle.
Two questions:
Which one experiences a greater
change in momentum?
NIETHER!!! They are the same.
Which one experiences a greater
change in velocity?
The Bullet.
4-20
Two billiard balls collide
elastically on a table as
shown below. Which picture best represents the
motion of ball #2 after the collision?
#2
#1
A
Bonk!
#1
B
C
4-20A
Two billiard balls collide
elastically on a table as
shown below. Which picture best represents the
motion of ball #2 after the collision?
#2
#1
A
Bonk!
#1
B
C
4-25
Type Question Here
4-25A
3 kg
2.5 m/s
1.8 m/s
2 kg
Momentum of LH-cart = (3 kg)(2.5 m/s) = +7.5 kg m/s
Momentum of RH-cart = (2 kg)(-1.8 m/s) = -3.6 kg m/s
Total Momentum = +3.9 kg m/s
After collision ==> 3.9 kg m/s = (5 kg)v
v = (3.9 kg m/s)/(5 kg) = +0.78 m/s
How many triangles5-5
are there in this figure?
5-5A
35
5-10
Name the actor
and movie that
produced this famous quote:
“Boards don’t hit back.”
5-10A
Bruce Lee, in
Enter the Dragon
5-15
The word “Hamster” means what
in German?
A)
B)
C)
D)
Bacon Mix
Hoarder
Rodent
Nocturnal
5-15A
The word “Hamster” means what
in German?
A)
B)
C)
D)
Bacon Mix
Hoarder
Rodent
Nocturnal
5-20
As of early 2008, what is the smallest
commercial car in the United States?
The Smart Car
5-20A
What California gold-rush
entrepreneur used his knowledge
of bouncing collisions to design a
nearly 90% efficient water wheel?
Lester 5-25A
A. Pelton,
inventor of the Pelton water wheel
Daily Double
3 kg
2.5 m/s
1.8 m/s
2 kg
Two carts collide and stick together as shown
above. What is the velocity of the carts after
they’ve collided? Assume there is no friction.