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Two people sit opposite each other on the edge of a rotating disk of radius, R, and negligible mass. One person has a mass of 40kg, the other of 50kg. The disk is rotating at 30 revs/min. What is the rotational kinetic energy if R=1.5m?

Rotational Kinetic Energy (KE) = (1/2) x Moment of Inertia (I) x (Angular Velocity (w) ) 2 I=SUM(MR 2 ) = 40 x (1.5) 2 + 50 x (1.5) 2 = 90 x (1.5) 2 = 202.5 kgm 2 w= 30 revs / min = 30 x (2π/60) = π (rad/s)K...
JS
Answered by Joe S. • Physics tutor
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How do conservative plate boundaries cause earthquakes?

-Tectonic plates (which can be either continental or oceanic) slide past each other either in opposite directions or in the same direction but at different speeds-This causes friction between the plates to b...
LH
Answered by Laura H. • Geography tutor
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Integrate Sin(x)Cos(x)dx.

Integral(Sin[x]Cos[x]dx) can be calculated. The method is to recognise that the trigonometric identity of 2Sin[x]Cos[x]=Sin[2x] can be applied. This would transform the integral into Integral(0.5Sin[2x]) whi...
DD
Answered by Daniel D. • Maths tutor
5185 Views

How do I know when to use "Akkusativ" or "Dativ"

The word "Dativ" comes from latin "dare", meaning "to give". In German, it's the third grammar case. This case is used when someone directly gives, says or declares something to...
JC
Answered by Jordi C. • German tutor
20444 Views

Explore the characterisation of the three sisters in the opening of the play, ‘King Lear’.

Shakespeare opens King Lear by introducing the audience to the King’s failing health, and his requirement to distribute his wealth and property amongst his three daughters; Cordelia, Goneril and Reagan. The ...
ZS
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