Physics 113 –Morning Session, Summer 2006
Participation Points #5
To be stapled on top of #4,3,2,1 and turned
in with Exam#3 to receive extra credit
Student’s name ________________________ Total previous points
accumulated:
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14.1 Static equilibrium. Give the horizontal force
applied at the highest point to keep a wheel of mass M from rolling down a
slope inclined at angle θ to the horizontal.
15.1
SHM. Before take-off your keys
connected to a thread make 90 cycles per minute, while the plane is
accelerating they make 91 cycles per minute. What is the plane acceleration?
15.2
SHM. Two blocks, one on top of
the other are undergoing SHM of angular frequency 10 rad/s
since the lower one is laying on a frictionless surface and connected to a
spring. Friction between the two blocks is what keeps them move together. When
the amplitude of the SHM is increased to 60cm, the upper block starts to slip,
what is μs?
16.1
Wave
properties. Given
y=2 cos(π(x-t/2))
where x,y are in cm, and t in seconds. Provide (a)
amplitude (b) wavelength (c) period (d) speed (e) direction of propagation of
the wave.
16.2
Wave
on a string. Mass
m1 is vertically attached to a wire of linear density 1.5 g/m, the
other end of the wire runs through a pulley and is horizontally tied to a wall.
The speed of the transverse wave in the horizontal section of the wire is
30m/s. If a mass m2 is added to m1 this speed becomes
40m/s. Find m2.
16.3
Interference. You are in an aircraft
with two engines running at 500rpm and 506 rpm. How often do you hear the sound
intensity increase as a result of wave interference?
17.1
Standing
waves. A
1m long string is clamped at both ends (a) what is the longest wavelength? (b) if the speed is 50m/s, what is the lowest standing-wave
frequency?
17.2
Doppler
effect.
A fire truck’s siren wails at rest at 1200Hz. However you hear it
at 1500Hz when the truck is approaching, how fast is the truck going?
18.1 Bouyancy.
How much helium (density 0.18 kg/m3) is needed to
lift a balloon carrying two people in a basket, with the total mass except air
is 280kg. Repeat for hot air, with density 10% less than that of surrounding
atmosphere