Saturday, December 02, 2006

Weeks Report

Teaching Physics 12 and Science 10 at my practicum school. Its not difficult but the fact that I the students are ultimately those of my host teacher forces me to more vigilant about my teaching. At the end of the day it will (or should) improve my pedagogic skills.

The following is an example of a quiz that I set for the Grade 12 class.

Work, Energy and Satellite Quiz

Total Marks: 15

Physics Grade 12


Read the Questions carefully
Show all working. Remember Units and Sig Figs.
Good Luck!!

1.A 70 kg skier starts from rest and skis down a 450 hill of vertical height 350m. If the coefficient of kinetic friction is 0.1
How much energy is lost to friction from the top to bottom? (1)
What is the speed at the bottom? (2)
If another hill of inclination 30 degrees sits at the bottom of the first hill. How far will the skier go up the second hill. Assuming the friction on the second hill is 0.1 as well? (1)

2. A horizontal spring of k=40N/m is elongated 25 cm then released. The spring has a mass of 750g at one end.
What is its maximum speed? (1)
At what point(s) is Ep: Ek = 4:1 for one cycle? (2)
If 12% of the energy is lost to the surroundings per complete cycle. How many cycles will it take for the Total Energy of the system to drop to less than 5% of the original total energy? (1)
Give a rough sketch of an Fres vs t graph for a single cycle starting from compression? (1)

3. A 300 kg satellite is released from the surface of Vulcan-5. The planet has six times the mass of the Earth but three times its radius.
Mass of Earth = 5.98 x 10^24kg Radius of Earth (re) = 6.38*10^6m

What is the planet’s escape velocity at the surface? (2)
What is the planet’s Ep at an orbital radius = 8 re? (1)
How much additional energy is needed to escape from the orbit mentioned in b? (2)
What is the theoretical Schwartzchild radius of the planet? (1)
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