Homework answers / question archive / 1) In the custom setting, choose the ‘My Object’ option in the material drop down box

1) In the custom setting, choose the ‘My Object’ option in the material drop down box

Physics

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1) In the custom setting, choose the ‘My Object’ option in the material drop down

box. Set the mass of your object to 4 kg. Adjust the volume to find the minimum

volume needed to make the object float.

 

 

 

Density and Buoyancy 

 

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it float?
Styrofoam	.75 kg	5 L	.15 kg/L	yes
Wood	2.0 kg	5 L	.4 kg/L	yes
Ice	4.6 kg	5 L	.92 kg/L	Yes
Brick	10 kg	5 L	2 kg/L	no
Aluminum	13.5 kg	5 L	2.7 kg/L	no

 

 

 

 

2. How does the density of a large piece of aluminum compared to a small piece?

 

 

 

SAME MASS

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it float?
Blue	5 kg	5.00 L	1 kg/L	no
Yellow	5 kg	5.00 L	1 kg/L	yes
Green	5 kg	2.5 L	2 kg/L	no
Red	5 kg	1.25 L	4 kg/L	no

 

 

SAME VOLUME

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it float?
Blue	6 kg	5.0 L	1.2 kg/L	NO
Yellow	8 kg	5.0 L	1.6 kg/L	NO
Green	4 kg	4.0 L	1 kg/L	YES
Red	2 kg	2.0 L	1 kg/L	YES

 

 

 

3. Looking at the data on the previous page, what must be true about the density of

 an object in order for it to float?

 

 

 

 

4. Calculate the density of the blue object in this section.

 

 

 

5. Explain why both the yellow and red objects float when they have different sizes.

Mystery Section:

 

 

6. Before you start, pick an object that you think will float.

 

 Pick an object that you think will sink.

 

 

 

 

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it float?
A	65.14 kg	103.38 L	.63 kg/L	no
B	.64 kg	100.64 L	.00635 kg/L	yes
C	4.08 kg	104.08 L	.0392 kg/L	yes
D	3.10 kg	103.10 L	.03 kg/L	yes
E	3.53 kg	101.0 L	.0349 kg/L	no

 

 

 

 

 

 

 

7. In the Custom section describe the difference between how Styrofoam and ice

 floated. Also explain why you think this is the case?

 

 

 

8. In the Same Mass Section discuss what was interesting about the blue object’s

behavior in the water.

 

 

9. In the Mystery Section, click on the “Show Table” button. What is the most dense

 object on the list? Write its density as well.

 

 

 

 

10. List something you learned from this activity.

 

 

 

 

 

 

 

 

 

Buoyancy: How Does Buoyant Force Act on Objects in a Fluid?

Directions:

 

1. How can you use a block and the other tools on the Intro tab to determine the density of the “Oil”?

 

 

 

2. Challenge: Explain how an object that is more dense than water can be kept afloat by

placing it on an object that is less dense than water

 

 

 

 

 

Appendix A

 

1. During the span of the second time interval, the ball begins at 2 m/s and ends at 4 m/s. What is the average speed of the ball during this 1-s interval? What is its acceleration?

 

 

 

 

2. An auto starting from rest has a constant acceleration of 4 m/s^2. How far will it go in 5s?

 

 

 

3. How far will an object released from rest fall in 1s? In this case the acceleration is g=9.8 m/s^2

 

 

4. If it takes 4s for an object to fall to the water when released from the golden gate bridge, how high is the bridge.

 

 

 

 

 

5. Definitions: