Name: KEY
!
81
Force
Pushing
Momentum
Date:
! ! Box—Final
!
Period:
! Various
! similar
!
! are! being Impulse-Momentum
boxes
pushed for 10 secondsQuiz
across a floor by a net horizontal force as show
1. below.
Bill pushes
various
similar
boxes
for
10
seconds
across
a floor
horizontal
The mass of the boxes and the net horizontal force for
eachwith
caseaisnet
given
in the indicated figures.
force as shown below. The mass of the boxes and the net horizontal force for each case
is given in the indicated figures.
Rank the final momentum for each box from the greatest momentum to the least momentum. All box
havethe
an final
initialmomentum
velocity of 10
to the
is positive.
Rank
form/s.
eachMotion
box from
theright
greatest
momentum to the least
momentum. All boxes have an initial velocity of 10 m/s. Motion to the right is positive.
10 kg
F = 100 N
15 kg
F = 50 N
20 kg
F = 75 N
B
J = 100 N * 10 s A
= 1000 N*s
p_final
=
(50
N
* 10 s) + (15 kg * 10 m/s)
J = Δp = p_final - p_initial
=
500
N*s
+ 150 kg*m/s
p_final = J + p_initial
=
650
N*s
[kg*m/s]
p_final = 1000 N*s + (10 kg)*(10 m/s)
p_final = 1100 N*s [kg*m/s]
20 kg
F = 50 N
D
p_final = 10 * (50 + 20)
= 700 N*s [kg*m/s]
F
Greatest 1_______
C
p_final = (75 N * 10 s) + (20 kg *10 m/s)
= 750 N*s + 200 kg*m/s
= 950 N*s [kg*m/s]
10 kg
F = 75 N
15 kg
F = 100 N
E
p_final = 10 * (75 + 10)
= 850 N*s [kg*m/s]
F
p_final = 10 * (100 +15)
= 1150 N*s [kg*m/s]
B
A
C
E
D
2_______
3_______
4_______
5_______
6_______
Least
Highest
1________
2________
3________
4________
5________
6________
Lowest
Please
carefully
explain
the reasoning
for your
ranking and
show work
as necessary.
Or, all the final momenta are the same.
Please carefully explain your reasoning.
How sure were you of your ranking? (circle one)
Basically Guessed
Sure
1
2
3
4
5
6
81
7
8
Very Sure
9
10
T. O’Kuma
Physics Ranking Tasks
86
Mechanics
Name:
!
81
Force
Pushing
Momentum
Date:
! ! Box—Final
!
Period:
! Various
! similar
!
! are! being Impulse-Momentum
boxes
pushed for 10 secondsQuiz
across a floor by a net horizontal force as show
1. below.
Christina
pushes
various
similar
boxes
for
10
seconds
a case
floor is
with
a net
The mass of the boxes and the net horizontal forceacross
for each
given
in the indicated figures.
horizontal force as shown below. The mass of the boxes and the net horizontal force for
each case is given in the indicated figures.
Rank the final momentum for each box from the greatest momentum to the least momentum. All box
havethe
an final
initialmomentum
velocity of 10
to the
is positive.
Rank
form/s.
eachMotion
box from
theright
greatest
momentum to the least
momentum. All boxes have an initial velocity of 10 m/s. Motion to the right is positive.
20
10 kg
kg
F = 100 N
10
15 kg
kg
F = 50 N
20 kg
F = 75 N
B
J = 100 N * 10 s A
= 1000 N*s
p_final = (50 N * 10 s) + (10 kg * 10 m/s)
J = Δp = p_final - p_initial
= 500 N*s + 100 kg*m/s
p_final = J + p_initial
= 600 N*s [kg*m/s]
p_final = 1000 N*s + (20 kg)*(10 m/s)
p_final = 1200 N*s [kg*m/s]
10
20 kg
kg
F = 50 N
p_final = 10 * (50 + 10)
= 600 N*s [kg*m/s]
D
C
p_final = (75 N * 10 s) + (20 kg *10 m/s)
= 750 N*s + 200 kg*m/s
= 950 N*s [kg*m/s]
15
10 kg
kg
F = 75 N
15 kg
F = 100 N
p_final = 10 * (75 + 15)
= 900 N*s [kg*m/s]
p_final = 10 * (100 + 15)
= 1150 N*s [kg*m/s]
E
F
A
F
C
E
B,D
Greatest 1_______
2_______
3_______
4_______
5_______
6_______ Least
Please carefully explain the reasoning for your ranking and show work as necessary.
Highest 1________ 2________ 3________ 4________ 5________ 6________ Lowest
Or, all the final momenta are the same.
Please carefully explain your reasoning.
How sure were you of your ranking? (circle one)
Basically Guessed
Sure
1
2
3
4
5
6
81
7
8
Very Sure
9
10
T. O’Kuma
Physics Ranking Tasks
86
Mechanics
Name:
!
81
Force
Pushing
Momentum
Date:
! ! Box—Final
!
Period:
! Various
! similar
!
! are! being Impulse-Momentum
boxes
pushed for 10 secondsQuiz
across a floor by a net horizontal force as show
1. below.
Gary pushes
various
similar
boxes
for
10
seconds
across
floorcase
withisagiven
net horizontal
The mass of the boxes and the net horizontal force foraeach
in the indicated figures.
force as shown below. The mass of the boxes and the net horizontal force for each case
is given in the indicated figures.
Rank the final momentum for each box from the greatest momentum to the least momentum. All box
havethe
an final
initialmomentum
velocity of 10
to the
is positive.
Rank
form/s.
eachMotion
box from
theright
greatest
momentum to the least
momentum. All boxes have an initial velocity of 10 m/s. Motion to the right is positive.
15
10 kg
kg
20
15 kg
F = 100 N
F = 50 N
A
10
20 kg
kg
F = 75 N
B
J = 100 N * 10 s = 1000 N*s
p_final = (50 N * 10 s) + (20 kg * 10 m/s)
J = Δp = p_final - p_initial
= 500 N*s + 200 kg*m/s
p_final = J + p_initial
= 700 N*s [kg*m/s]
p_final = 1000 N*s + (15 kg)*(10 m/s)
p_final = 1150 N*s [kg*m/s]10
15
20 kg
kg
10 kg
kg
F = 50 N
F = 75 N
p_final = 10 * (50 + 10)
= 600 N*s [kg*m/s]
20
15 kg
kg
F = 100 N
p_final = 10 * (75 + 15)
= 900 N*s [kg*m/s]
D
C
p_final = (75 N * 10 s) + (10 kg *10 m/s)
= 750 N*s + 100 kg*m/s
= 850 N*s [kg*m/s]
p_final = 10 * (100 + 20)
= 1200 N*s [kg*m/s]
E
F
A
F
E
C
B
D
Greatest 1_______ 2_______ 3_______ 4_______ 5_______ 6_______ Least
Highest
1________
2________
3________
4________
5________
6________
Lowest
Please
carefully
explain
the reasoning
for your
ranking and
show work
as necessary.
Or, all the final momenta are the same.
Please carefully explain your reasoning.
How sure were you of your ranking? (circle one)
Basically Guessed
Sure
1
2
3
4
5
6
81
7
8
Very Sure
9
10
T. O’Kuma
Physics Ranking Tasks
86
Mechanics
2. The minimum force that is needed to crack an egg is 25 N. Based on this fact, state
reasonable values of force and time for the two following cases: an egg hitting the
wall and an egg hitting a sheet. Assume that the force-time graph is shaped like a
rectangle. The figures below are NOT drawn to scale.
Egg hitting a wall!
!
!
!
Answers will vary. The force here should be
greater than or equal to 25 N. The time
should be relatively short.
!
Egg hitting a bed sheet
Answers will vary. The force here should
be less than 25 N and the time should be
longer than the case for when the egg is
hitting a wall.
The force multiplied by the time, the impulse, should be equal to each other in each case because the
change in momentum will be the same. The egg will be moving from a non-zero velocity to zero velocity
when it is stopped by the wall or the sheet.
b) What is the corresponding impulse for the values for force and time you selected?
How did you determine the impulse?
The impulse is the force multiplied by the time. The impulse is determined by either computing the area
of the rectangle above or finding the product of force and time. Values will vary depending on which values
of force and time were chosen.
c) Now assume that the force-time graph for the egg hitting the bed sheet is shaped like
a semi-circle. What is the maximum force that the egg will experience?
J = area under curve = area of semi-circle = 1/2 * (area of circle)
J = 1/2 (𝛑* r^2)
(2* J)/ 𝛑 = r^2
Fmax
√((2*J)/ 𝛑) = r
The radius of the semi-circle was calculated where the radius is
equal to the maximum force that the egg will experience in this
case. Answers will vary since the impulse, J, is different.
d) If the mass of the average egg is 0.05 kg, what is the change in velocity (Δv) that the
egg experiences [use the impulse from part (b)] ?
What are my known values? m = 0.05 kg J = (from previous part)
J = Δp = m*Δv
Δv = J/m
Actual answers will vary according to the impulse in part (b).