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A DVD is dropped from rest. The DVD does not reach terminal velocity before it hits the ground. Explain how the acceleration of the DVD varies from the instant it is dropped until just before it hits the ground.

In the instant when the DVD is dropped, it will have an acceleration of g, with no drag force acting on it as it is not moving. As the DVD accelerates downwards, the drag force acting on it increases and so ...
DH
Answered by Dylan H. • Physics tutor
4451 Views

A kettle is found to output 65J when its input energy is 100J. What is the efficiency of the kettle, and what happens to the rest of the energy?

Efficiency=useful energy /input energy x 100, so for the kettle, efficiency = 65/100 x 100 = 65% efficient. The rest of the energy is wasted as heat energy in the kettle/sound energy.
JL
Answered by Joshua L. • Physics tutor
22943 Views

What is red shift?

Red shift is the lengthening ('stretching') of the wavelength of electromagnetic radiation emitted from a body moving away from the observer. This process occurs as the EM radiation loses energy while it pas...
EJ
Answered by Elis J. • Physics tutor
4690 Views

Describe and explain the vertical motion of a parachutist which jumps out of an aeroplane at time t=0 and then releases the parachute shortly after reaching terminal velocity at time t=T. (Assume air resistance is not negligible).

We need to understand both what this question is asking of us, and what the question tells us. We are asked to investigate the motion of the parachutist, therefore in this case we need to apply Newton’s Laws...
TD
10982 Views

What's the difference between a bayron and a meson?

A baryon is a particle that is made up of three quarks (which are fundamental particles) bound by the strong force. A meson, on the other hand, is a particle which is made up of one quark and one antiquark. ...
JB
Answered by Josh B. • Physics tutor
12094 Views