Question

A bullet leaves a rifle with a muzzle velocity of 521 m/s. While accelerating through the barrel of the rifle, the bullet moves a distance of 0.840 m in 0.003 seconds. Determine the acceleration of the bullet.

So I basically used the formula:

Change in position= (Initial velocity*Change in time) + (Acceleration((Change in time)^2))/2) to solve for a, my acceleration.

So 0.840= 521(0.003) + 0.000009/2 (a)

So 0.840- 1.563= -0.723= 0.000009/2 (a)

-0.723*2= -1.446= 0.000009a

-1.446/0.000009 = -160666.6667= a

so my acceleration= -160666.6667

But i'm confused. i thought the bullet should be accelerating logically, not decelerating. am i even right? Where did I go wrong?

Answer 1

never mind, i think i found my mistake. 521m/s is the final velocity, not initial. thanks guys

Answer 2

Acceleration is any change in velocity. You can slow down, speed up, or turn. BTW, try not to use the term deceleration. It's best to use negative acceleration.