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A 12V lamp, 36W is switched on for 1 hour. Find the energy supplied by the battery.

E = P*t = 36 * 3600 = 1.3 * 10⁵ J

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A student heats a bar of chocolate in the microwave for one minute. When they remove the bar they observe that there are patches of melted chocolate with unmelted chocolate between them. Suggest the mechanism of how this happens.

This question is about standing waves, the bar of chocolate melts only in the positions where antinodes are formed on the standing wave as they transfer the most energy as they have the greatest amplitude...

Answered by Haydn D. • Physics tutor

7125 Views

On the line of centres between the Earth and the Moon, there is a point where the net gravitational force is zero. Given that the distance between the two is 385,000 km, and that the Earth has a mass 81x that of the Moon, how far is this point from Earth?

Here, we must consider Newton's Law of Universal Gravitation. This states that the gravitational force acting between two bodies is proportional to the masses of each body and inversely proportional to th...

Answered by Phil R. • Physics tutor

6424 Views

How can we derive the 'suvat' equations of motion v=u+at and s=(u+v)t/2

v=u+at Using a velocity time graph with constant acceleration, (graph provided as visual aid in tutorial) with initial velocity u and final velocity v, we can see that the graph is a straight line. ...

Answered by Isobel D. • Physics tutor

34160 Views

Why are values for gravitational potential always negative?

This is all down to how gravitational potential is defined. The gravitational potential at a point is defined as the work done per unit mass to move a mass from infinity to the point in the gravitational ...

Answered by James S. • Physics tutor

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