Post on 19-Jan-2016
+
Newton’s Laws & Momentum Review
+Practice Quiz
Write the question on the front of each flashcard
Write your best answer on the back of each flashcard
+Question 1:
Ball A and Ball B collide and stick together.
Which equation is best for finding the final velocity of the Ball A – Ball B system?
F=(m x v)/t
(mballA x ViballA) + (mballB x ViballB) = (mballA + mballB)Vf
v = vf – vi
= m v
+Question 2:
Ball A and Ball B collide and stick together. Ball A has a mass of 30g. Ball B has 60g of mass.
Find the final velocity of the Ball A – Ball B system
+Question 3:
What does the Law of Conservation of Momentum say happens to momentum during a collision?
+Question 4:
Ball A and Ball B collide and stick together. Ball A has a mass of 30g. Ball B has 60g of mass.
Is momentum conserved during the collision between ball A and ball B?
Support your answer with evidence(evidence can be calculations or an explanation of observations
from class activities)
+Question 5:
Ball A and Ball B collide and stick together. Ball A has a mass of 30g. Ball B has 60g of mass.
The collision between ball A and ball B took .3 seconds.
Calculate the force ball A exerted on ball B.
+Question 6:
PREDICT the force ball B exerted on ball A.
Support your prediction with evidence. How do you know your prediction is correct?
(cite a class activity)
+Question 7:
When an egg smashed into your head, the egg is broken but your head is fine.
How does the force the egg experiences compare to the force your head experiences?
+Question 8:
When an egg smashed into your head, the egg is broken but your head is fine.
Why is the egg smashed but your head is not damaged in this collision?
+Question 9:
When an egg smashed into your head, the egg is broken but your head is fine.
If you wanted to increase the collision force, what could you do?
+Correct Your Answers
Cross out incorrect answers
Write down correct answers (for long answers use your own words)
+Answer 1:
Ball A and Ball B collide and stick together.
Which equation is best for finding the final velocity of the Ball A – Ball B system?
F=(m x v)/t
(mballA x ViballA) + (mballB x ViballB) = (mballA + mballB)Vf
v = vf – vi
= m v
+Answer 2:
Ball A and Ball B collide and stick together. Ball A has a mass of 30g. Ball B has 60g of mass.
Find the final velocity of the Ball A – Ball B system
(mballA x ViballA) + (mballB x ViballB) = (mballA + mballB)Vf
(30gx+20cm/s) + (60gx-15cm/s) = (30g+60g)Vf
+600 + -900 = 90vf
-300/90 = vf
Vf = -3.33 cm/s
+Answer 3:
What does the Law of Conservation of Momentum say happens to momentum during a collision?
Momentum does not change during a collision.
The total momentum before a collision equals the total momentum after a
collision.
+Answer 4:
Pbefore = mballAViballA + mballBViballB
30(+20) + 60(-15)
-300 = Pbefore
Pafter = (mballA + mballB)VfballA-B
(30 + 60)-3.33
-300 = Pafter
Momentum is equal before and after.
Tennis ball experiment: Calculated momentum Momentum before
equaled momentum after (with a little error)
Sticky Situations: Used equation to predict
Vf assuming momentum was conserved
Prediction was supported by evidence suggesting momentum is conserved in collisions
Calculations Observations from Activities
Is momentum conserved during the collision between ball A and ball B?
Support your answer with evidence(evidence can be calculations or an
explanation of observations from class activities)
+Answer 5:
Ball A and Ball B collide and stick together. Ball A has a mass of 30g. Ball B has 60g of mass.
The collision between ball A and ball B took .3 seconds.
Calculate the force ball A exerted on ball B.
F=(m x v)/t(30)(-3.33-+20)/.3
(-699.9)/.3
F = -2333 g cm/s/s
+Answer 6:
PREDICT the force ball B exerted on ball A.
+2333 g cm/s/s
Support your prediction with evidence. How do you know your prediction is correct?
(cite a class activity)
1) Clay activity: clay always equally flat on both sides shows equal force from opposite directions
2) Tennis ball activity: calculations of force show forces equal in size (with minor error) and in
opposite directions (opposite signs)
+Answer 7:
When an egg smashed into your head, the egg is broken but your head is fine.
How does the force the egg experiences compare to the force your head experiences?
The forces are equal in size and opposite in direction
+Answer 8:
When an egg smashed into your head, the egg is broken but your head is fine.
Why is the egg smashed but your head is not damaged in this collision?
The force on the egg is equal to the force on your head.
Your head has more mass so more force is needed to change the velocity of your head. The egg less mass
so the force causes a big change in velocity. This change in velocity breaks the egg.
+Answer 9:
When an egg smashed into your head, the egg is broken but your head is fine.
If you wanted to increase the collision force, what could you do?
Increase the mass of the head, egg or both
Increase the velocity of the head, egg or both
Decrease the collision time for the head/egg system