Notecard Quiz

Name ______________ Date _______ Period __Activity 83, Analysis 3b

Activity 86 Analysis1. How did you rank the stability of the carts

that had three different centers of mass? Describe the observations that determined your rankings.

2. How did the higher center of mass affect the cart’s motion after it hit the barrier?

– When the cart hits the barrier, a force is applied to the lower part of the car, causing it to decelerate

– The inertia of the part of the cart’s mass that is above the barrier cause it to continue to move forward

3. Imagine three identical barrels, one empty, one full of water, and one half-full of water.

c. Explain why the lowest center of mass is located there.• The center of mass is lowest on barrel B, because there is

more mass in the lower half of the barrel than the top half, making the concentration of mass below the center.

• Even distribution of mass puts the center of mass in the middle of the other two barrels

d. Relatively high center of mass and low mass

4. Your friend’s parents want to haul some lumber in their station wagon. His parents are not sure whether to put the lumber in the wagon or tie it on the roof rack. What advice do you give them? Explain in terms of center of mass.

• Put the wood in the wagon• Lower center of mass• Safer because it makes the vehicle more stable5. Why do you think pickups and SUVs tend to roll over more

often than passenger cars of similar mass? Explain in terms of center of mass.

• Due to higher ground clearance and overall profile, SUVs have a higher center of mass

• Easier for center of mass to move outside of the wheelbase and cause the vehicle to roll over.

Activity 86 Major Concepts

Read page 427 in PH

BuoyancyTitle: The Penny Boat Lab

Purpose: To demonstrate buoyancy by building a ship out of aluminum foil.

Problem: How many pennies will your ship hold?

Hypothesis: I predict my foil ship will hold ____ pennies before it sinks.

Data/Observations:

Boat Name Number of Pennies

Table 1: My Boat

Boat Name Number of PenniesMake 16 rows- one for each ship

Mean (average)Median (middle value)

Table 2: Class Results

Data/Observations: (cont.)

You will draw 3 accurate pictures:

My Boat Picture

Most Pennies Boat

Least Pennies Boat

I’m not sure what to do!• Read the procedure!• Read the procedure!• Read the procedure!• Read the procedure!• Read the procedure!

Thoroughly dry the pennies after you have tested your boat. Lay your pennies out on a paper towel and pat them dry. Then dry each penny as you put it back in the cup. Don’t destroy your boat when you are done.

To Sink or Not to Sink,That is the Question!

Happy Sailing!

Buoyancy Video

http://www.youtube.com/watch?v=2afDLk-JzEY&feature=related