TEACHER'S TEACHERS'S TEACHER'S TEACHER'S
Ken Cheney
10/29/2005
5:07/C0
Physics 31A Test Two
1. SUPERMAN
Superman is climbing a rope of breaking strength 300 pounds. If
he weighs 110 pounds what is his maximum upward acceleration?
32*(300-110)/110
a. 16.9, *b. 55.3, c. .633, d. .0181, e. 1.73
2. BLOCKS, TABLE, AND PULLEY
A 73 Kg block rests on a frictionless table. It is connected to a
hanging 220 kg block by a frictionless pulley. How many m/s/s do the
two blocks accelerate?
220*9.8/(73+220)
a. 2.33, *b. 7.36, c. 11.3, d. 19.8, e. 26.8
3. FREE FALL
You want to practice zero g, i.e. not feeling any gravity. You
plan to have your plane fly in a vertical circle of radius 810 feet.
What velocity (ft/s) is required to cancel gravity at the top of the
circle?
SQR(810*32)
a. 49.3, b. 108, *c. 161, d. 195, e. 571
4. KEPPLER PERIOD
Durive Keppler's law connecting period and the radius of the orbit
of a satellite.
5. SUPER POWDER
A 120 pound skier starts down a 39 degree slope with no friction.
After decending 200 feet vertically she comes to 79 feet of level snow
with a mu of .51. She then goes up a 35 degree slope, again with no
friction.
How many feet (verticaly) is she above the level snow when she
stops?
Hint: Use conservation of energy and it is easy!!
200-.51*79
*a. 160, b. 225, c. 327, d. 475, e. 675
6. DRAG POWER
What horsepower is required to accelerate a 540 kg dragster at 1.5
g's if it is moving 300 km/hr? 1 HP=746 watts
540*1.5*9.8*300*1000/(3600*746)
Physics 31A Test Two - Ken Cheney - V. 5:07/C COPY 0 PAGE 2
a. 353, b. 502, c. 673, *d. 887, e. 1,170
7. FOG AND FRICTION
You are driving on a very foggy night and can only see 76 feet
ahead. The coefficient of friction is .35.
How many ft/sec can you drive assuming that your reactions are so
quick that no time at all is lost in putting on the brakes?
SQR(64*76*.35)
*a. 41.3, b. 67.2, c. 96.9, d. 138, e. 154