Energy Principle Blank Notes Template

Lecture 06-1: Energy Principle
Sections 6.1-6.3 in Matters & Interactions
The Energy Principle:



Rest Energy of a Particle:

Erest = mc2

What is a particle?
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Energy of a moving particle:
E = mc2 + K

Q6.2.a
A ball whose mass is 2 kg travels at a velocity of < 0, –3, 4> m/s. What is the kinetic energy of
the ball?




Q6.2.b
A ball whose mass is 2 kg travels at a velocity of < 0, –3, 4> m/s. What is the rest energy of the
ball?

, Q6.2.c
Consider an electron (mass 9 x 10-31 kg) moving with speed v = 0.9c. What is its rest energy?




Q6.2.d
Consider an electron (mass 9 x 10-31 kg) moving with speed v = 0.9c. What is its (total) particle
energy?




Q6.2.e
Consider an electron (mass 9 x 10-31 kg) moving with speed v = 0.9c. Its rest energy is 8.1 x
10-14 J and its total particle energy is 1.86 x 10-13 J. What is its kinetic energy?




Calculate the electron's rest, total, and kinetic energy in the previous example in eV.