Energy An electron with no

potential energy or kinetic energy has ____ total energy.

A. zeroB. positiveC. negative

How fast? A particle with mass ___

travel at speed c. Light ___ travel at speed c.

A. can, canB. cannot, cannotC. can, cannotD. cannot, can

Energies Which of the following is true?

A. A particle’s rest energy cannot be greater than its kinetic energy.

B. A particle’s kinetic energy cannot be greater than its rest energy.

C. A particle’s kinetic energy cannot be greater than its total energy.

D. More than one of the above is true.

PAL Week 6 Wednesday

In SI units, the mass of an electron is 9.11X10-31 kg.

In relativity-friendly units, the mass of an electron is 511 keV/c2.

1. An electron has speed 15,000 km/s (which is 5% of c).A. Find its rest energy in J. 8.199e-14 JB. Find its total energy in J. 8.209e-14C. Find its kinetic energy in J, using the

relativistic equation. 1.0268e-16D. Find the % error incurred due to using

the non-relativistic kinetic energy equation. 0.19%

2. An electron has speed 0.4 c.A. Find its rest energy in eV. 511 keVB. Find its total energy in eV. 557.5

keVC. Find its kinetic energy in eV , using

the relativistic equation. 46.5 keVD. Find the % error due to using the

non-relativistic kinetic energy equation. 12%