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Using Newton's law of universal gravitation, show that T^2 is proportional to r^3 (where T is the orbital period of a planet around a star, and r is the distance between them).

(Lets consider a simple planetary system composed of a planet orbiting a star. the gravitational force between the two is given by F=(GMm)/(r 2 ). Assuming the planet also moves in a circular orbit, we can c...
KS
Answered by Karanvir S. • Physics tutor
30872 Views

What is the difference between a longitudinal and a transverse wave?

Waves that go up and down in a curvy shape like you would draw on a piece of paper are called transverse waves. Scientifically, these are when the particles move in a direction that is perpendicular (90) fro...
SF
Answered by Sarah F. • Physics tutor
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What is the stress in a cylindrical rod of 10.0cm diameter when loaded by 50.0N force at each end?

Stress = Force/Area and cross sectional area of a cyclinder = pi.r 2 As diameter = 10.0cm=0.1m r=0.05m so area = 3.14*0.05 2 = 0.00785m 2 As the force is 50.0N the stress is 50/0.00785=6369Nm -2 or 6.37kPa t...
RH
Answered by Rowan H. • Physics tutor
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Given I climb two steps every second and I have a mass of 50kg, what is the power output of my legs in kilowatts? (3 significant figures)

(There is a diagram showing stairs with steps that are 20cm high) Power = Energy/TimeEnergy required to climb one step = Work Done = Force DistanceForce = Weight = m g = 50 9.81 = 490.5NEnergy = 490.5 0.2 = ...
TG
Answered by Toby G. • Physics tutor
2578 Views

In the photoelectric effect, what happens as you increase the frequency of light keeping the same intensity constant?

E=hf, so as you increase the frequency of light, the energy of each photon hitting the metal surface is greater. Thus the electrons liberated from the surface of the metal have a greater maximum kinetic ener...
AJ
Answered by Alexander J. • Physics tutor
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