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A-bullet-of-mass-180g-is-fired-horizontally-into-a-fixed-wooden-block-with-a-speed-of-24m-s-if-the-bullet-is-brought-to-rest-in-0-4sec-by-a-constant-resistance-calculate-the-distance-moved-by-




Question Number 197155 by otchereabdullai@gmail.com last updated on 09/Sep/23
 A bullet of mass 180g is fired    horizontally into a fixed wooden    block with a speed of 24m/s. if the   bullet is brought to rest in 0.4sec by a  constant resistance, calculate the  distance moved by the bullet in the  wood
$$\:{A}\:{bullet}\:{of}\:{mass}\:\mathrm{180}{g}\:{is}\:{fired}\: \\ $$$$\:{horizontally}\:{into}\:{a}\:{fixed}\:{wooden}\: \\ $$$$\:{block}\:{with}\:{a}\:{speed}\:{of}\:\mathrm{24}{m}/{s}.\:{if}\:{the}\: \\ $$$${bullet}\:{is}\:{brought}\:{to}\:{rest}\:{in}\:\mathrm{0}.\mathrm{4}{sec}\:{by}\:{a} \\ $$$${constant}\:{resistance},\:{calculate}\:{the} \\ $$$${distance}\:{moved}\:{by}\:{the}\:{bullet}\:{in}\:{the} \\ $$$${wood} \\ $$
Answered by AST last updated on 09/Sep/23
v^2 =u^2 +2as⇒−24^2 =2as  s=ut+(1/2)at^2 ⇒s=9.6+((a(0.4)^2 )/2)=9.6+0.08a  ⇒((−576)/(2a))=9.6+0.08a⇒0.16a^2 +19.2a+576=0  ⇒a=−60ms^(−2) ⇒s=9.6−4.8=4.8m
$${v}^{\mathrm{2}} ={u}^{\mathrm{2}} +\mathrm{2}{as}\Rightarrow−\mathrm{24}^{\mathrm{2}} =\mathrm{2}{as} \\ $$$${s}={ut}+\frac{\mathrm{1}}{\mathrm{2}}{at}^{\mathrm{2}} \Rightarrow{s}=\mathrm{9}.\mathrm{6}+\frac{{a}\left(\mathrm{0}.\mathrm{4}\right)^{\mathrm{2}} }{\mathrm{2}}=\mathrm{9}.\mathrm{6}+\mathrm{0}.\mathrm{08}{a} \\ $$$$\Rightarrow\frac{−\mathrm{576}}{\mathrm{2}{a}}=\mathrm{9}.\mathrm{6}+\mathrm{0}.\mathrm{08}{a}\Rightarrow\mathrm{0}.\mathrm{16}{a}^{\mathrm{2}} +\mathrm{19}.\mathrm{2}{a}+\mathrm{576}=\mathrm{0} \\ $$$$\Rightarrow{a}=−\mathrm{60}{ms}^{−\mathrm{2}} \Rightarrow{s}=\mathrm{9}.\mathrm{6}−\mathrm{4}.\mathrm{8}=\mathrm{4}.\mathrm{8}{m} \\ $$
Commented by otchereabdullai@gmail.com last updated on 09/Sep/23
thanks sir
$${thanks}\:{sir} \\ $$

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