Calculating Angular Velocity of a Shell Exiting a Barrel | Physics Homework

[paragchitnis]

Homework Statement

A shell acquires the initial velocity v = 320m/s, having made n = 2.0 turns inside the barrel whose length is equal to l = 2.0m. Assuming that the shell moves inside the barrel with uniform acceleration, find the angular velocity of its axial rotation at the moment when the shell escapes the barrel.

Homework Equations

vf = vi + at
This equation can be used for linear as well as angular velocity
x = vit + at^2
vf^2 - vi^2 = 2ax

The Attempt at a Solution

The given answer is 2pi nv/l = 2.0 x 10³ rad./s

 

[housemartin]

How much time it took to make those n = 2 turns? then if you know this time, can you find angular velocity?

 

[paragchitnis]

How much time it took to make those n = 2 turns? then if you know this time, can you find angular velocity?

Time is not given. But let us consider it take ts for n = 2 turns. can we get the answer in terms of t?

 

[housemartin]

Time is what you have to find, you know final ant initial linear velocities and the length of the barrel, from here you can find ts. Angular velocity is measured in radians per second. And two rotations is how much radians? And you when you find time it took to make those two rotations, then...? ;]