Item 1 Part A An object has a total energy that is 2 0 times

Item 1 Part A An object has a total energy that is 2 0 times its rest energy What is its speed? Express your answer using two significant figures. v087 Submit Correct Part B What is the ratio of the object\'s relativistic kinedc energy to its rest energy? Express your answer using two significant figures. Submit My Answers Give Incorrect; Try Again; 2 attempts remaining

Solution

A)

2mc^2 = mc^2 / sqrt(1 - v^2/c^2)
sqrt(1 - v^2/c^2) = 1/2

1 - v^2/c^2 = 1/4

v^2 = (3/4)c^2
v = 0.87c

B) Total Energy (E) = K + mc^2
Kinetic energy = E - mc^2
E = 2mc^2
Therefore, K = mc^2
Also rest mass energy = mc^2

Then ratio = 1