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Question Number 72560 by Umar last updated on 30/Oct/19

Commented by Umar last updated on 30/Oct/19

$$\mathrm{solve}3\mathrm{and}4\mathrm{pls}$$

Commented by TawaTawa last updated on 30/Oct/19

$$\left(3\mathrm{i}\right)$$$$\mathrm{We}\mathrm{have},\mathrm{u}=10\mathrm{m}/\mathrm{s},\mathrm{v}=15\mathrm{m}/\mathrm{s},\mathrm{a}=1\mathrm{m}/{\mathrm{s}}^2.$$$$\mathrm{The}\mathrm{time}\left(\mathrm{t}\right)=?$$$$\mathrm{a}=\frac{\mathrm{v}-\mathrm{u}}{\mathrm{t}}$$$$\therefore 1=\frac{15-10}{\mathrm{t}}$$$$\therefore \mathrm{t}=5\mathrm{s}$$$$\left(3\mathrm{ii}\right)$$$${\mathrm{v}}^2={\mathrm{u}}^2+2\mathrm{as}$$$$\therefore {15}^2={10}^2+2\left(1\right)\mathrm{s}$$$$\therefore 225=100+2\mathrm{s}$$$$\therefore 2\mathrm{s}=225-100$$$$\therefore 2\mathrm{s}=125$$$$\therefore \mathrm{s}=\frac{125}{2}$$$$\therefore \mathrm{s}=62.5\mathrm{m}$$$$\left(3\mathrm{iii}\right)$$$$\mathrm{s}=\left(\frac{\mathrm{v}+\mathrm{u}}{2}\right).\mathrm{t}$$$$\therefore {\mathrm{v}}^2={\mathrm{u}}^2+2\mathrm{as}$$$$\therefore {\mathrm{v}}^2=0^2+2\left(1\right)\left(100\right)$$$$\therefore {\mathrm{v}}^2=0+200$$$$\therefore {\mathrm{v}}^2=200$$$$\therefore \mathrm{v}=\sqrt{200}$$$$\therefore \mathrm{v}=14.14\mathrm{m}/\mathrm{s}$$$$$$

Commented by TawaTawa last updated on 30/Oct/19

$$\left(4\right)$$$${\mathrm{v}}^2={\mathrm{u}}^2+2\mathrm{as}$$$$\therefore {20}^2={50}^2+2(-10).\mathrm{s}$$$$\therefore 400=2500-20\mathrm{s}$$$$\therefore 400-2500=-20\mathrm{s}$$$$\therefore -2100=-20\mathrm{s}$$$$\therefore \mathrm{s}=\frac{-2100}{-20}$$$$\therefore \mathrm{s}=105\mathrm{m}$$

Commented by TawaTawa last updated on 30/Oct/19

$$\mathrm{Sir}\mathrm{MrW}\mathrm{please}\mathrm{check}.$$

Commented by Umar last updated on 30/Oct/19

$$\mathrm{Thank}\mathrm{u}\mathrm{sir}$$

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