Question Number 73279 by byaw last updated on 09/Nov/19
Answered by mr W last updated on 09/Nov/19
$$\mathrm{40}={v}_{\mathrm{0}} ×\mathrm{4}+\frac{\mathrm{1}}{\mathrm{2}}{a}×\mathrm{4}^{\mathrm{2}} \\ $$$$\Rightarrow\mathrm{10}={v}_{\mathrm{0}} +\mathrm{2}{a}\:\:\:…\left({i}\right) \\ $$$$\mathrm{72}={v}_{\mathrm{0}} ×\mathrm{6}+\frac{\mathrm{1}}{\mathrm{2}}{a}×\mathrm{6}^{\mathrm{2}} \\ $$$$\Rightarrow\mathrm{12}={v}_{\mathrm{0}} +\mathrm{3}{a}\:\:\:…\left({ii}\right) \\ $$$$\left({ii}\right)−\left({i}\right): \\ $$$${a}=\mathrm{2}\:{m}/{s}^{\mathrm{2}} \\ $$$$ \\ $$$${from}\:\left({i}\right): \\ $$$${v}_{\mathrm{0}} =\mathrm{10}−\mathrm{2}×\mathrm{2}=\mathrm{6}\:{m}/{s} \\ $$$$ \\ $$$${v}_{{t}=\mathrm{10}} =\mathrm{6}+\mathrm{2}×\mathrm{10}=\mathrm{26}\:{m}/{s} \\ $$$$ \\ $$$${v}_{{s}=\mathrm{600}} =\sqrt{{v}_{\mathrm{0}} ^{\mathrm{2}} +\mathrm{2}{as}}=\sqrt{\mathrm{6}^{\mathrm{2}} +\mathrm{2}×\mathrm{2}×\mathrm{600}}=\mathrm{2}\sqrt{\mathrm{609}} \\ $$$$=\mathrm{49}.\mathrm{36}\:{m}/{s} \\ $$