A golf player hits a 0.045\, \text {kg}0.045kg0, point, 045, start text, k, g, end text golfball that is initially at rest, changing its momentum by 4.2\, \dfrac {\text{kg}\cdot \text m}{\text s}4.2 s kg⋅m 4, point, 2, start fraction, start text, k, g, end text, dot, start text, m, end text, divided by, start text, s, end text, end fraction.