An 8 g bullet leaves the muzzle of a rifle with
a speed of 611.9 m/s.
What constant force is exerted on the bullet
while it is traveling down the 0.8 m length of
the barrel of the rifle?
Answer in units of N.

Respuesta :

Answer: 1872 N

Explanation:

This problem can be solved by using one of the Kinematics equations and Newton's second law of motion:

[tex]V^{2}=V_{o}^{2} + 2ad[/tex] (1)

[tex]F=ma[/tex] (2)

Where:

[tex]V=611.9 m/s[/tex] is the bullet's final speed (when it leaves the muzzle)

[tex]V_{o}=0[/tex] is the bullet's initial speed (at rest)

[tex]a[/tex] is the bullet's acceleration

[tex]d=0.8 m[/tex] is the distance traveled by the bullet before leaving the muzzle

[tex]F[/tex] is the force

[tex]m=8 g \frac{1 kg}{1000 g}=0.008 kg[/tex] is the mass of the bullet

Knowing this, let's begin by isolating [tex]a[/tex] from (1):

[tex]a=\frac{V^{2}}{2d}[/tex] (3)

[tex]a=\frac{(611.9 m/s)^{2}}{2(0.8 m)}[/tex] (4)

[tex]a=234013.5063 m/s^{2} \approx 2.34(10)^{5} m/s^{2}[/tex] (5)

Substituting (5) in (2):

[tex]F=(0.008 kg)(2.34(10)^{5} m/s^{2})[/tex] (6)

Finally:

[tex]F=1872 N[/tex]