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Derive an expression for the centripetal acceleration of a body in uniform circular motion.

(I assume familiarity with positions represented by vectors and differentiation of trigonometric functions). Consider the coordinates of a point moving in a circle of radius r around the origin. The equation...
HA
Answered by Hubert A. • Physics tutor
4090 Views

The energy transferred from the water in the kettle to its surroundings in 2 hours is 46 200 J. The mass of water in the kettle is 0.50 kg. The specific heat capacity of water is 4200 J/kg °C. What is its temperature after 2 hours?

The water loses 4200 J/kg °C * 0.5 kg = 2100 J/°C As it's lost 46,200 J in total (regardless of the time it took for this to happen), it must have reduced in temperature by 46,200 J / 2100 J/°C = 22°C. Assum...
DB
Answered by Dewi B. • Physics tutor
27299 Views

Explanation of alpha scattering experiment

Alpha particles which are made up of 2 protons and 2 neutrons (overall positive charge) are fired towards a thin sheet of gold. To ensure any deflection of the alpha particles is only due to the gold sheet t...
JM
Answered by James M. • Physics tutor
20541 Views

if -3 + -4 is -7, is -3 x -4 =-12 (also negative)

I would use the x-y graph to explain the multiplication of negative numbers I would also start with 4 x 3, then work my way towards negative numbers, e.g 4x2, 4x1 ......4x-1, 4x-2 Then I would go from 4 x -3...
SK
Answered by Syeda K. • Physics tutor
2205 Views

Calculate the threshold frequency for a metal with a work function of 3eV

The equation for work function is: W = hf So, this is rearranged to: f = W/h where h is planck's constant. Therefore, if we know the work function then we can work out the threshold frequency. Don't forget t...
AW
Answered by Anna W. • Physics tutor
98645 Views