Answer:
1/2 Hz
Explanation:
A simple harmonic motion has an equation in the form of
where A is the amplitude, 
is the angular frequency and 
is the initial phase.
Since our body has an equation of x = 5cos(π t + π/3) we can equate 
and solve for frequency f
f = 1/2 Hz
Answer: T is greater
Explanation:
Since the elevator is moving against gravity more work will be done on the rope
T= m(g+a)
If it produces 20J of light energy in a second, then that 20J is the 10% of the supply that becomes useful output.
20 J/s = 10% of Supply
20 J/s = (0.1) x (Supply)
Divide each side by 0.1:
Supply = (20 J/s) / (0.1)
<em>Supply = 200 J/s </em>(200 watts)
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Here's something to think about: What could you do to make the lamp more efficient ? Answer: Use it for a heater !
If you use it for a heater, then the HEAT is the 'useful' part, and the light is the part that you really don't care about. Suddenly ... bada-boom ... the lamp is 90% efficient !
