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A phone is knocked off a table 800cm of the ground. If the phone is 650g a) what is the gravational potential of the phone? b)what speed will the phone hit the floor at? c)How long will it take for the phone to hit the floor?

UNITS - SI UNITS: 800cm --> 0.8m 0.65kg

a) Ep= mg(change) height

Ep=0.65kg * 9.81m/s² * 0.80m

Ep=5.10 Joules (J)

b) Gravational Potential = Kinetic energy

Answered by Julia J. • Physics tutor

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A cup of boiling water (100 degrees C) (0.2kg) transfers 20 000J of heat to its surrounding in 1 hour. What temperature is the water in the kettle after 1 hour?

To answer this we need to use the equation Q = MC(T1-T2)

We want to know what T2 is (ie the temperature after one hour).

So rearrange the equation to get T2 = T1 - Q/MC

No substitute ...

Answered by Callum J. • Physics tutor

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Why is it that spectral lines emitted from stars in distant galaxies appear to be shifted towards the red end of the electromagnetic spectrum?

Spectral lines are caused by electrons within atoms being excited up energies levels by absorbing specific frequencies of light (this produces absorption lines- dark lines in an otherwise continuous spect...

Answered by Louise C. • Physics tutor

5560 Views

How might an uncharged object become positively charged? (e.g. AQA Higher specimen paper 1)

Ask student what causes charge, i.e. motion of electrons.

So answer is that electrons move away from the object leaving it positively charged, or move onto a neutral object leaving it negatively ch...

Answered by Joanna W. • Physics tutor

14990 Views

what would be the mass required to keep an object with a mass of 250kg orbiting at a constant distance of 100km with a linear velocity of 100m/s?

the linear speed of an orbiting body is given by the equation sqrt(GM/2r) where M is the mass of the attracting body, G is the gravitational constant and r is the distance between the two bodies' centres ...

Answered by Michael A. • Physics tutor

1905 Views