The energy E and momentum p of a moving body of mass m are related by some equation. Given that c represents the speed of light, identify the correct equation
- E2=pc2+m2c4
- E2=pc2+m2c2
- E2=p2c2+m2c4
- E2=p2c2+m2c2
Answer
(3) E2=p2c2+m2c4
Solution
Every term of a correct equation has the dimensions of E2= M2L4T-4.
[p2c2]= M2L2T-2 L2T-2= M2L4T-4 ✓
[m2c4]=M2 L4T-4 ✓
[pc2]= ML3T-3 ✗, [m2c2]= M2L2T-2 ✗
E2=p2c2+m2c4
Answer: (3)