TEACHER'S TEACHERS'S TEACHER'S TEACHER'S
Ken Cheney
10/28/2005
5:06/C0
Physics 31A Test One
1. UNITS ON MARS
The average gravitational acceleration on the surface of Mars is
13 fleeps per rands squared. How many zips per lits squared is this?
1 fleep = 10 zips, 28 rands= 4.8 lits.
13*10*(28/4.8)^2
*a. 4,420, b. 2.77 E6, c. 1.05 E7, d. 2.21 E7, e. 3.68 E7
2. SIG FIG
Write the following in the form 34=3.4 x 10 to make it clear how
many significant figures there are. Explain your logic. a. 8.0 x
1986.35 b. 0.08 x 19.86 c. 1.000-0.005 d. 2.3586 + 0.3 e. 32.789/3
3. CAT JUMP
A cat jumps from the ground to a height of .91 m. If you define
time as zero at the top of the jump when did the cat LEAVE the ground?
(seconds)
-SQR(2*.91/9.8)
a. .431, b. .862, c. .238, d. .0431, *e. -.431
4. VEC POLY 2
Draw a vector polygone to scale to find the magnitude of the
resultant of the following vectors: 130 at zero degrees, 110 at 135
degrees, 170 at 270 degrees, and 82 at -45 degrees.
SQR((130+110*COS(135)+82*COS(-45))**2+(110*SIN(135)-170+82*SIN(-45))**2)
a. 41.3, *b. 186, c. 1,210, d. 16.5, e. 1,600
5. RIGHT FIELD FENCE
What is the highest fence that a ball hit with a velocity of 120
ft/sec at an angle of 25 degrees can clear at a distance of 230 feet?
Ignore the initial height of the ball.
230*SIN(25)/COS(25)-16*(230/COS(25))**2/120/120
a. 5.51, b. 18.5, c. 25.3, *d. 35.7, e. 97.2
6. NOT A PARABULA
Show why it is often said that projectiles follow a parabolic
path: y proportional to x squared. Explain the incorrect asumptions in
this derivation.