An Electron Has a Relativistic Momentum Of $1.1 \times 10 ^ { - 21 } \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$

Short Answer

An electron has a relativistic momentum of $1.1 \times 10 ^ { - 21 } \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$ . What percent of its total energy is its kinetic energy? ( $m _ { \text {electron } } = 9.11 \times 10 ^ { - 31 } \mathrm {~kg} , c = 3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s }$ )