Conceptual Physics Labs – Chapter 6

Mastronicola Page 1 of 5

Name _______________________________

Where appropriate – ALWAYS show your formulas and your work!

Use the back of your paper if you need to. Displacement

This activity takes place outside and requires several calculations.

1) Go outside and find the corner of the building.

2) Take the three cones provided and lay out a LARGE right triangle, with

the corner of the building as the 90⁰ corner. (Don’t measure yet)

3) Now, measure the distance from cone 1 to cone 2 _________________

4) And, the distance from cone 2 to cone 3 ________________________

Calculate the displacement from cone 1 to cone 3.

Since your measuring tape isn’t in metrics – please convert to meters

before calculating your displacement.

Plotting Vectors

Add the following vectors to find the resultant vector.

Plot the resultant vector (XR) on the grid.

X1 = (5,3)m

X2 = (-5,0)m

X3 = (5,2)m

1

2 3

Corner of building

Conceptual Physics Labs – Chapter 6

Mastronicola Page 2 of 5

Projectile Motion & Velocity Vectors A ball tossed upward has initial velocity components of 29.4m/s vertical and 5m/s horizontal. The position of the ball is shown at 1-second intervals. Air resistance is negligible and g=9.8m/s2. Fill in the boxes, writing in the values of velocity components ascending, and your calculated resultant velocities descending. Show your work on the back. Remember Pythagoras.

5m/s

5m/s

29.4m/s

Conceptual Physics Labs – Chapter 6

Mastronicola Page 3 of 5

Comparing Angular Speed, Linear Speed and Distance (and a little history…) Back in the day, records were labeled by how many rotations per minute they spun, so this record spins at 45 rpm. CDs spin at various speeds depending upon the machine, AND, the machine reads at a constant linear velocity, so the rpm differs depending upon where it is being read from – however, the average rpm was about 350 rpm when they first came out. Measure the diameter of the record you are given. Calculate the radius._____________________ Measure the diameter of the CD you are given. Calculate the radius._____________________ Some more information you’ll need: 45s spin:

45 rotations per minute60 = 0.75 rotations per second

=

CDs spin:

350 rotations per minute60 = 5.83 rotations per second

=

With this information, calculate the linear speed in m/s at the edge of each of these disks (assuming 350 rpm for the CD at the edge):

RECORD CD

Conceptual Physics Labs – Chapter 6

Mastronicola Page 4 of 5

Centripetal/Centrifugal Force This one also takes place outside. Using the bucket that is half-full of water, choose someone in your group to spin the bucket over their head several times (quickly). Now sketch the bucket and explain the forces applied. Note – there is a towel there, but you won’t need it if you do this right. Universal Gravitation You knew we had to do this one… A man on the moon with a mass of 90.0 kilograms weights 146 newtons. The radius of the moon is 1.74 x 106 meters. Find the mass of the moon.

Conceptual Physics Labs – Chapter 6

Mastronicola Page 5 of 5

Center of mass Find the center of mass of the United States by using the plump bob (weighted string) set up and the laminated map of the U.S. Hang the map from the hook at the various holes punched in the map. Using the dry-erase marker, draw a line on the map along the plump line. This is the center of mass. Where do they intersect? Balancing Act Show me that you can balance the two items I give you. I’ll initial the box when you’re done.