Physics for engineer/Force and motion

Force and motion

Matter remains stationary when ther is no force acts on it

$F=0$ . O

Matter moves when there is force acts on it

$F=0$ . F --> O -----> O

Matter is at equilibrium whensum of all forces act on it equal zero

$F=0$ . F --> O -----> O

Gravity Force

Attractive force to pull matter downward toward the earth

$F_{g}=mg=m{\frac {M}{h^{2}}}$

$g={\frac {M}{h^{2}}}$

$h={\sqrt {\frac {mM}{F_{g}}}}={\sqrt {\frac {M}{g}}}$

Impulse

Impulse to move a moment

$F_{p}=m{\frac {v}{t}}={\frac {p}{t}}$

$v={\frac {F_{p}t}{m}}={\frac {p}{m}}$

$h={\sqrt {\frac {mM}{F_{g}}}}={\sqrt {\frac {p}{F_{g}}}}$

Motion caused by multi force

For any matter hangs above the earth

$F_{g}=F_{p}$

$mg=m{\frac {v}{t}}$

$g=a={\frac {mM}{h^{2}}}$

$h={\sqrt {\frac {mM}{g}}}$

$v=gt$

$t={\frac {v}{g}}$