A rifle bullet with a mass of 11.5 g traveling toward the right at 251 m/s strikes a large bag of sand and penetrates it to a depth of 23.7 cm. determine the magnitude and direction of the friction force (assumed constant) that acts on the bullet.

Question

Physics

Jaylyn Underwood

28 May, 05:25

A rifle bullet with a mass of 11.5 g traveling toward the right at 251 m/s strikes a large bag of sand and penetrates it to a depth of 23.7 cm. determine the magnitude and direction of the friction force (assumed constant) that acts on the bullet.

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Kiersten Fry · Answer 1

To look for the acceleration, it will come from:

vf^2=v0^2+2ad

where:

vf = final velocity = 0

v0 = initial velocity = 251 m/s

a = acceleration

d = distance traveled = 0.237 m

0=251^2+2a (0.237)

a = - 251 ^2 / (2*0.237) = - 132 913.502 m/s/s

we find the force from:

F = ma = 0.0115kg * (-1.32x10^5m/s/s) = - 1518 N

the negative sign shows that the force is in the direction contradictory the bullet's motion