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When a wave source moves towards a receiver, does the receiver encounter an increase in wave frequency, wave speed or both?
Suppose a piano tuner hears 3 beats per second when listening to the combined sound from her tuning fork and the piano note being tuned. After slightly tightening the string, she hears 2 beats per second. Should she loosen the string or should she further tighten the string? Why?
An unknown force accelerates a 6500kg moving van from -3m/s to -13m/s in a time of 2s. In Newtons, how large is the force?
If the electric forces of repulsion between two 2.80-C charges have magnitude 17.0 N, how far apart are they?
- You are coasting downhill at a constant velocity of 1.00 m/s2 on your longboard. You and the longboard have a mass of 67.5 kg. The angle of the hill is 12.0o above the horizontal. Draw a free-body diagram for you and the longboard.What is the magnitude of each force acting on you and the longboard?
Three students observe a toy car rolling across a level floor until it slows to a stop. After the observation, they
make these statements:
Max:
“Energy is conserved, but friction turned it into heat, warming the floor and wheels.”
Chris:
“But it stops. Energy is not conserved. The car’s kinetic energy disappeared.”
Sam:
“But energy can’t just disappear. It must have become potential energy.”
Which student was correct?
(a) Calculate the energy stored in the capacitor.
(b) The battery is then disconnected from the capacitor; the capacitor retains its charge. Calculate the energy stored in the capacitor if the distance between the plates is now increased to 10.00mm. Account for the difference in your answer of (a) and (b) above.
A string of fixed length has a 2nd harmonic frequency of 680 Hz but when it is vibrating in the 3rd harmonic its wavelength is 0.52 m.
a) Calculate the 1st harmonic frequency.
b) Calculate the 3rd harmonic frequency.
c) Calculate the speed of the wave energy along this string.
A violin string vibrating in the 1st harmonic produces a note of frequency 316 Hz. If the speed of the wave energy along the violin string is 280 m/s, calculate the length of the string.
The 3rd harmonic frequency of a guitar string is 768 Hz.
a) Calculate its 1st harmonic (fundamental) frequency. (2 marks)
b) Calculate its 4th harmonic frequency. (2 marks)
