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Explain how Pumped-storage hydropower (PSH) can store energy.

The system consists of 2 reservoirs at different elevations, where the water can flow between them but through a hydroelectric power station. The higher elevation reservoir releases its water at higher energ...
CK
Answered by Chris K. • Physics tutor
4023 Views

Explain why a smoke alarm works by emitting and detecting alpha radiation instead of gamma or beta radiation.

Alpha radiation isn't very penetrating and so is absorbed and stopped by smoke particles. This causes a change in count rate when there is smoke present. This change in count rate allows the alarm to be trig...
FM
Answered by Fin M. • Physics tutor
11992 Views

Two trains are heading in opposite directions on the same track. Train X has a mass of 16000kg and a speed of 2.8m/s. Train Y has a mass of 12000kg and a speed of 3.1m/s. At what speed do the joined trains move off together immediately after the collison?

Remembering that if the velocities are in different directions they have different signs:Total momentum before=Total momentum afterMomentum=mass x velocityTotal momentum before= (16000x2.8)+(12000x(-3.1))=76...
CJ
Answered by Carys J. • Physics tutor
2006 Views

A diver of mass 60kg stands on the end of a diving board (2m in length). Calculate the upward force exerted on the retaining spring which is 30cm from the start of the diving board.

Here we have a typical moments question. The start of the diving board is the pivot (draw a picture)To answer this question we need to know that sum of the clockwise moments must equal the sum of the anticlo...
SA
Answered by Sophie A. • Physics tutor
4246 Views

A ball is dropped from a height of 20m. How long does it take for the ball to reach ground?

Use SUVAT. Height is 20m, initial speed is 0m/s, acceleration is 10m/s^2, and you need to find time. Therefore use s = ut + 1/2 at^2, and rearrange to get a value for t as t = 2s.
LT
Answered by Lauren T. • Physics tutor
7870 Views