As an Electron Slows Down From $0.9980 c$ To $0.5000 c$ , How Much Momentum Does It Lose

Short Answer

As an electron slows down from $0.9980 c$ to $0.5000 c$ , how much momentum does it lose? $( c$ $= 3.0 \times 10 ^ { 8 } \mathrm {~m} / \mathrm { s } , m _ { \text {electron } } = 9.11 \times 10 ^ { - 31 } \mathrm {~kg}$ )