Los Altos High School
Physics
Mr. Randall
2009-2010
www.LAPhysics.com
adam.randall@mvla.net
0.
The Earth has an equatorial radius of 6.38 x 106 m.
A.
Predict the speed of a person standing on the equator with respect to the
Earth’s axis of rotation.
B.
Predict the speed of the flag pole stationed near the front of the school with
respect to the Earth’s axis of rotation. LAHS is approximately 37° North of
the equator.
C.
Sketch a graph of the speed as a function of the latitude.
1.
Consider a golf cart driving as fast as it can while turning a huge, horizontal circle. The
coefficient of friction between the surface of the road and tires is measured to be µs = 0.88.
A.
B.
C.
D.
Predict the maximum speed the cart can travel without sliding out of the circle.
Predict the minimum time required to make one complete circle.
Sketch a graph of v vs. µs.
Sketch a graph of T vs. µs.
2.
Consider an amusement park ride called the ROTOR. The Rotor is essentially a large hollow
cylinder rapidly rotating around its central axis with people standing against the inside wall. As
the Rotor accelerates to safe operating speed static friction, acting between the Rotor’s wall and
the people pressed up against it, increases such that the floor can be removed without anyone
falling out the bottom.
A.
Predict the minimum speed of someone on the Rotor before the floor
can be safely removed: r = 4.0m, µs = 0.59.
B.
Sketch a graph of V vs. µs
C.
If the speed of the Rotor were to (increase/decrease) people would
begin to slide downward.
If the coefficient of static friction were to (increase/decrease) the
minimum operating speed of the Rotor would decrease.
D.
If the speed of the rotor increased above the minimum safe operating speed, would a
it rise upward and fly out of the top
person riding
3.
A.
B.
C.
D.
E.
Consider a model airplane whirling around in a horizontal circle at constant speed.
The plane is not actually flying. A cable, attached to the plane, supplies a tension
force that keeps the model from freefalling to the ground and also forces it
centripetally accelerate. The length of the cable = 1.5 m. The cable extends 30.0°
with respect to the vertical. The model airplane’s mass = 0.25 kg
Predict the tension in the cable.
Sketch a graph of the tension in the cable as a function of θ.
Predict the radius of the circle, r.
Predict the speed of the plane, v.
Predict the time period, T.
θ
4.
Consider a 70.0 kg circus clown sitting on a force scale attached to the bench seat of a Ferris
wheel. When the wheel is turning at its safe operating speed it takes 10.0 s to complete one
revolution. The distance from the center of the Ferris wheel to where the clown is sitting is
20.0 m.
A.
B.
Predict the clown's apparent weight at the top of the Ferris wheel.
Predict the clown's apparent weight at the bottom of the Ferris wheel.
/»]
aa
,-i
i.
•- /V\\f
-K) r
B]
8
0 KV\
r
0
-j-
« /O
<rv\\f
=.
<^n
3 *•
=
r
*w>» '
. ^^"
W » 7 « - «3 1?
fT
fl.
,.
— ^-<~S'
CS, lotyfi f £f-tejt*x
r
f«6
i/^r
'
T
Y* (2,6?
j
/____^——~~~~
(
nl
JM
T^P
5.
You have been assigned the job a placing a Classic Rock Digital Radio Satellite (C+D)R+S
into geosynchronous orbit around the Earth. A geosynchronous orbit is one that maintains the
same position above the Earth at all times. The Earth's mass is 5.98 x 1024 kg and it's
equatorial radius is 6.38 x 106 m..
A.
Could the satellite stay in orbit directly above Los Altos High School (LAHS)? Briefly explain
B.
C.
D.
E.
Predict
Predict
Predict
Predict
the time period, T, of the geosynchronous orbit.
the radius of the orbit.
the height above the surface of the Earth the satellite orbits.
the speed of the satellite in geosynchronous orbit.
l^6 **
0 **•
l
' t^Ks*-*^ **- //
6.
Assuming the Earth undergoes uniform circular motion in it's orbit around the Sun. If the
average radius of the orbit is 1.5 x 1011m, show that the mass of the sun is 2.0 x 1030 kg.
v
-2TiC
r.
V
2
T=
T
0, -
S~
-r-2&'Z