Mechanics Questions

Question Number 102553 by aurpeyz last updated on 09/Jul/20

Commented by aurpeyz last updated on 09/Jul/20

$$\mathrm{pls}\:\mathrm{help} \\$$

Commented by aurpeyz last updated on 09/Jul/20

Commented by Rio Michael last updated on 10/Jul/20

$$\mathrm{Force}\:=\:\mu{F}_{{N}} \:+\:\mathrm{mg}\:\mathrm{sin}\:\theta \\$$$$\Rightarrow\:{F}\:=\:\left(\mathrm{0}.\mathrm{4}\right)\left(\mathrm{10}\:×\:\mathrm{9}.\mathrm{8}\right){N}\:+\:\left(\mathrm{10}\right)\left(\mathrm{9}.\mathrm{8}\right)\mathrm{sin}\:\mathrm{60}{N} \\$$

Answered by mr W last updated on 10/Jul/20

$${F}\:\mathrm{cos}\:\theta−{mg}\:\mathrm{sin}\:\theta\geqslant\mu\left({mg}\:\mathrm{cos}\:\theta+{F}\:\mathrm{sin}\:\theta\right) \\$$$${F}\:\left(\mathrm{cos}\:\theta−\mu\:\mathrm{sin}\:\theta\right)\geqslant{mg}\left(\mu\mathrm{cos}\:\theta+\mathrm{sin}\:\theta\right) \\$$$$\Rightarrow{F}\geqslant\frac{{mg}\left(\mu\:\mathrm{cos}\:\theta+\mathrm{sin}\:\theta\right)}{\mathrm{cos}\:\theta−\mu\:\mathrm{sin}\:\theta} \\$$$$\Rightarrow{F}\geqslant\frac{{mg}\left(\mu+\mathrm{tan}\:\theta\right)}{\mathrm{1}−\mu\:\mathrm{tan}\:\theta} \\$$$$\Rightarrow{F}\geqslant\frac{\mathrm{10}×\mathrm{9}.\mathrm{81}\left(\mathrm{0}.\mathrm{4}+\sqrt{\mathrm{3}}\right)}{\mathrm{1}−\mathrm{0}.\mathrm{4}×\sqrt{\mathrm{3}}}=\mathrm{681}\:{N} \\$$

Commented by aurpeyz last updated on 10/Jul/20

$$\mathrm{your}\:\mathrm{solution}\:\mathrm{is}\:\mathrm{great}\:\mathrm{Sir}.\:\mathrm{pls}\:\mathrm{explain}\:\mathrm{the}\:\mathrm{first}\:\mathrm{line}\:\mathrm{of}\:\mathrm{the}\:\mathrm{solution}.\:\mathrm{i}\:\mathrm{will}\:\mathrm{understand}\:\mathrm{the}\:\mathrm{rest} \\$$

Commented by aurpeyz last updated on 10/Jul/20

$$\mathrm{with}\:\mathrm{this}\:\mathrm{solution}\:\mathrm{it}\:\mathrm{seem}\:\mathrm{like}\:\mathrm{there}\:\mathrm{is}\:\mathrm{a}\:\mathrm{force}\:\mathrm{action}\:\mathrm{at}\:\Theta\:\mathrm{degrees}\:\mathrm{to}\:\mathrm{the}\:\mathrm{plane} \\$$

Commented by mr W last updated on 10/Jul/20

Commented by aurpeyz last updated on 10/Jul/20

$$\mathrm{where}\:\mathrm{F}\:\mathrm{is}\:\mathrm{the}\:\mathrm{horizontal}\:\mathrm{force}\:\mathrm{right}?\:\mathrm{so}\:\mathrm{i}\:\mathrm{will}\:\mathrm{just}\:\mathrm{have}\:\mathrm{to}\:\mathrm{resolve}\:\mathrm{to}\:\mathrm{get}\:\mathrm{the}\:\mathrm{answers}\:\mathrm{like}\:\mathrm{hou}\:\mathrm{did} \\$$

Commented by aurpeyz last updated on 10/Jul/20

$$\mathrm{Sir}\:\mathrm{Pls}\:\mathrm{check}\:\mathrm{Q}.\:\mathrm{102194}.\:\mathrm{what}\:\mathrm{will}\:\mathrm{be}\:\mathrm{the}\:\mathrm{direction}\:\mathrm{of}\:\mathrm{the}\:\mathrm{friction}? \\$$

Commented by mr W last updated on 10/Jul/20

$${in}\:{this}\:{question}\:{you}\:{should}\:{move} \\$$$${the}\:{object}\:{up}\:{to}\:{the}\:{plane}\:{and}\:{the} \\$$$${friction}\:{is}\:{always}\:{in}\:{the}\:{opposite} \\$$$${direction}\:{to}\:{the}\:{movement}\:{the}\:{object} \\$$$${tries}\:{to}\:{make}.\:{in}\:{this}\:{case}\:{it}\:{is} \\$$$${downwards}. \\$$$${but}\:{in}\:{Q}\mathrm{102194}\:{you}\:{don}'{t}\:{need}\:{to}\:{move} \\$$$${up}\:{the}\:{object},\:{you}\:{just}\:{need}\:{to} \\$$$${prevent}\:{it}\:{to}\:{move}\:{down},\:{in}\:{that}\:{case} \\$$$${the}\:{friction}\:{is}\:{upwards},\:{because}\:{the} \\$$$${object}\:{tries}\:{to}\:{move}\:{downwards}. \\$$

Commented by aurpeyz last updated on 10/Jul/20

$$\mathrm{i}\:\mathrm{understand}\:\mathrm{you}\:\mathrm{Sir}.\:\mathrm{thanks}\:\mathrm{alot}.\: \\$$

Commented by aurpeyz last updated on 11/Jul/20

$$\mathrm{Sir}\:\mathrm{cam}\:\mathrm{you}\:\mathrm{recomend}\:\mathrm{a}\:\mathrm{textbook}\:\mathrm{for}\:\mathrm{me}\:\mathrm{Sir}.\:\mathrm{that}\:\mathrm{will}\:\mathrm{help}\:\mathrm{me}\:\mathrm{with}\:\mathrm{all}\:\mathrm{of}\:\mathrm{this}? \\$$

Commented by mr W last updated on 11/Jul/20

$${no}\:{sir}.\:{not}\:{because}\:{i}\:{don}'{t}\:{want}\:{to}\:{tell} \\$$$${you},\:{but}\:{because}\:{i}\:{don}'{t}\:{know}\:{such}\:{a} \\$$$${book},\:{not}\:{because}\:{i}\:{don}'{t}\:{find}\:{the} \\$$$${books}\:{good}\:{enough},\:{but}\:{because}\:{i}\:{have} \\$$$${never}\:{read}\:{such}\:{a}\:{book}\:{since}\:{i}\:{left} \\$$$${the}\:{school}. \\$$

Commented by aurpeyz last updated on 11/Jul/20

$$\mathrm{okay}\:\mathrm{Sir} \\$$