Chapter 8 Rotational Kinetic Energy and Conservation of Energy Ranking Task 15 o
ID: 2034172 • Letter: C
Question
Chapter 8
Rotational Kinetic Energy and Conservation of Energy Ranking Task
15 of 21
Constants
The five objects of various masses, each denoted m, all have the same radius. They are all rolling at the same speed as they approach a curved incline.
Part A
Rank the objects based on the maximum height they reach along the curved incline.
Rank from largest to smallest. To rank items as equivalent, overlap them.
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smallest
largest
solid sphere?????????m=1.0kg
solid disk??????????m=0.5kg
solid cylinder???????????m=0.2kg
hollow sphere???????????m=0.2kg
hoop?????????m=0.2kg
The correct ranking cannot be determined.
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Approach the problem through conservation of energy. Notice that when you equate the initial energy (kinetic and rotational kinetic) and the final potential energy, you are equating two quantities that are both proportional to the mass. Therefore, the mass will cancel from the equation.
If a solid disk and a solid cylinder are of equal mass and radius, they will have the same moment of inertia.
If two of the objects reach the same height, stack the cards for the two objects to indicate this equality.Provide Feedback
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Incorrect. Incorrect; Try Again; 5 attempts remaining; no points deducted. Feedback.
Approach the problem through conservation of energy. Notice that when you equate the initial energy (kinetic and rotational kinetic) and the final potential energy, you are equating two quantities that are both proportional to the mass. Therefore, the mass will cancel from the equation.
If a solid disk and a solid cylinder are of equal mass and radius, they will have the same moment of inertia.
If two of the objects reach the same height, stack the cards for the two objects to indicate this equality. End of feedback.
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smallest
largest
solid sphere?????????m=1.0kg
solid disk??????????m=0.5kg
solid cylinder???????????m=0.2kg
hollow sphere???????????m=0.2kg
hoop?????????m=0.2kg
The correct ranking cannot be determined.
Explanation / Answer
by using conservation of energy,
1/2*m*v^2 + 1/2*I*w^2 = m*g*h
===> h=(m*v^2 + I*w^2)/(2*m*g)
here,
height(H) is depends on only I
and
the ranking of moment of inertia,
I_loop > I_hollow sphere > I_solid cylinder = I_solid disc > I solid sphere
the ranking of height,
h_loop > h_hollow sphere >h_solid cylinder = h_solid disc > h_solid sphere