Physics, 04.07.2020 18:01 nails4life324

a gun is fired at a 3cm thick solid wooden bar door. the bullet of a mass of 7g travels through the door and has its speed reduced from 450m/s to 175m/s assuming uniform resistance, what is the force of the wood on the bullet?

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Answer from: theangelsanchez

The force of the wood on the bullet = 20,052 N = 20.052 kN

Explanation:

According to the work-energy theorem, the work done by the wooden bar door in resisting the bullet is equal to the change in kinetic energy of the bullet.

Workdone by the wooden bar door in resisting the bullet = (Resisting force) × (Wood thickness)

Let the constant resisting force be -F (minus sign because it opposes motion)

Wood thickness = 3 cm = 0.03 m

Workdone by the wooden bar door in resisting the bullet = -F × 0.03 = (-0.03F) J

Change in kinetic energy of the bullet = (Final kinetic energy) - (Initial kinetic energy)

Final kinetic energy = ½mv²

m = 7 g = 0.007 kg

v = Final velocity = 175 m/s

Final kinetic energy = ½ × 0.007 × 175² = 107.1875 J

Initial kinetic energy = ½mv²

m = 7 g = 0.007 kg

v = Initial velocity = 450 m/s

Initial kinetic energy = ½ × 0.007 × 450² = 708.75 J

Change in kinetic energy of the bullet as it moves through the wooden bar door = 107.1875 - 708.75 = -601.5625 J

Workdone by the wooden bar door in resisting the bullet = Change in kinetic energy of the bullet as it moves through the wooden bar door

-0.03F = -601.5625

F = (601.5625/0.03) = 20,052.083333333 = 20052 N = 20.052 kN

Hope this Helps!!

Answer from: Quest

Acetic acid /əˈsiːtɪk/, systematically named ethanoic acid /ˌɛθəˈnoʊɪk/, is a colourless liquid organic compound with the chemical formula ch3cooh (also written as ch3co2h or c2h4o2). when undiluted, it is sometimes called glacial acetic acid. vinegar is no less than 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. acetic acid has a distinctive sour taste and pungent smell. in addition to household vinegar, it is mainly produced as a precursor to polyvinyl acetate and cellulose acetate. it is classified as a weak acid since it only partially dissociates in solution, but concentrated acetic acid is corrosive and can attack the skin.acetic acidnamespreferred iupac nameacetic acidsystematic iupac nameethanoic acidother namesvinegar (when dilute); hydrogen acetate; methanecarboxylic acid[1][2]identifierscas number64-19-7 3d model (jsmol)interactive image3dmetb00009 reference506007chebichebi: 15366 chemblchembl539 chemspider171 drugbankdb03166 echa infocard100.000.528ec number200-580-7e numbere260 (preservatives)gmelin reference1380iuphar/bps1058keggd00010 meshacetic+acidpubchem cid176rtecs numberaf1225000uniiq40q9n063p un number2789inchiinchi=1s/c2h4o2/c1-2(3)4/h1h3,(h,3,4) key: qtbsbxvteameqo-uhfffaoysa-n smilescc(o)=o

Answer from: Quest

the bal will not change its velocity.

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a gun is fired at a 3cm thick solid wooden bar door. the bullet of a mass of 7g travels through the...

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