## Physics (10th Edition)

a) 3.1 $\times$ $10^{3}$ J b) 2.2 $\times$ $10^{2}$ J
a) Work done = $\Delta$$E_{k} = 0.5mv^{2} - 0.5mu^{2} = 0.5(7.3)(29^{2}) - 0 \approx 3.1 \times 10^{3} J b) Work done = \Delta$$E_{k}$ = 0.5m$v^{2}$ - 0.5m$u^{2}$ = 0.5(0.0026)($410^{2}$) - 0 $\approx$ 2.2 $\times$ $10^{2}$ J