A 1200 W hair dryer used for 10 minutes uses as much energy as a 1000 W hair dryer run 12 minutes
What will be an ideal response?
This is correct: the power of 1200 W in the first case used for 10 min (600 s),
giving an energy use PDt = (1200 W)(600 s) = 720,000 J. In the second case, the power is
1000 W but the time is 12 min (720 s), giving an energy use of PDt = (1000 W)(720 s) =
720,000 J, exactly the same.
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Describe the orbits of the Kuiper Belt bodies
What will be an ideal response?
According to Newton, is a freely falling elevator an accurate inertial reference frame?
A. No, such a frame is accelerating toward the earth. B. It is not a real inertial frame, but we can treat it as one if we ignore external gravitational forces acting on objects inside the frame. C. Yes. D. It depends (explain).
A 3.0-kg object moving 8.0 m/s in the positive x direction has a one-dimensional elastic collision with an object (mass = M) initially at rest. After the collision the object of unknown mass has a velocity of 6.0 m/s in the positive x direction. What is M?
a. 7.5 kg b. 5.0 kg c. 6.0 kg d. 4.2 kg e. 8.0 kg
Two tuning forks sounding together result in a beat frequency of 4.00 Hz. If the frequency of one of the forks is 258 Hz, what is the frequency of the other?
a. 266 Hz or 250 Hz b. 129 Hz c. 254 Hz or 262 Hz d. 64.5 Hz e. 131 Hz