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Describe how a crumple zone on a car reduces injury to the driver in a crash.

During a crash the velocity of the car is reduced to zero. The deceleration of the car exerts a force on the driver causing injury. Without a crumple zone the change in velocity is instantaneous therefore a ...
TL
Answered by Thomas L. • Physics tutor
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What is meant by a uniform electric field?

Region which a force acts on a charged particle and the force is same at all points.
DH
Answered by Dave H. • Physics tutor
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Why do things get hot when electricity is pasted through them?

Electricity is the flow of electrons through a material. But for electrons to pass through a material they have to give up some energy, this is called a material's resistance. The energy that is lost from th...
PR
Answered by Peter R. • Physics tutor
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Two beakers contain water at room temperature. One contains 200ml, the other 400ml. If both beakers are heated above identical Bunsen burners, which of the two will take longer to boil?

The equation dQ = m c dT tells us how the temperature of an object changes when heat energy dQ is added. In this case the specific heat capacity c is the same for the contents of both beakers since we are he...
KJ
Answered by Keita J. • Physics tutor
7143 Views

A 4 metre long bar rotates freely around a central pivot. 3 forces act upon it: 7N down, 2m to the left of the pivot; 8N up, 1m to the left of the pivot; 4N up, 1m to the right of the pivot. Apply one additional force to place the bar in equilibrium.

Begin by calculating the current force and moment of the bar.Force: 8+4-7=5 (or vice versa)Moment: 7 2= 14 Nm anticlockwise 8 1= 8 Nm clockwise 4*1= 4 Nm anticlockwiseSum calculated moments: 14+4-8=10 (or vi...
MA
Answered by Michael A. • Physics tutor
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