An indestructible bullet 2.00cm long is fired straight through a board that is 10.0cm thick. The bullet strikes the board with a speed of 470 m/s and emerges with a speed of 270 m/s. (To simplify, assume that the bullet accelerates only while the front tip is in contact with the wood.) a). What is the average acceleration of the bullet through the board? ________m/s^2
b). What is the total time that the bullet is in contact with the board? (Enter the total time for the bullet to completely emerge from the board.) _________s
c.) What thickness of board (calculated 0.1 cm) would it take to stop the bullet, assuming that the acceleration through all boards is the same? ________cm

Respuesta :

Answer:

a)[tex]a=-7.4\times 10^{-5}\ m/s^2[/tex]

b)[tex]t=0.27\times 10^{-3}\ s[/tex]

c)s=14.92 cm

Explanation:

 Given that

u= 470 m/s

v = 270 m/s

s= 10 cm

a)

We know that

[tex]v^2=u^2+2as[/tex]

[tex]270^2=470^2+2\times a\times 0.1[/tex]

[tex]a=-7.4\times 10^{-5}\ m/s^2[/tex]

b)

v= u + a t

[tex]270=470-7.4\times 10^{-5}\times t[/tex]

[tex]t=0.27\times 10^{-3}\ s[/tex]

c)

To stop the bullet it means that the final velocity will be zero.

[tex]v^2=u^2+2as[/tex]

[tex]0^2=470^2-2\times 7.4\times 10^{-5} \times s[/tex]

s=14.92 cm