physics

A device is designed to measure the speed of a bullet. The device consists of two rotating disks, separated by a distance of d=0.850m, and rotating with an angular speed of 95.0 rad/s. The bullet first passes through the left disk and the through the right disk. It is found that the angular displacement between the two bullet holes is 0.240 rad. From these data, determine the speed of the bullet.

Can anyone please give me some hints to do it? Thanks a lot!

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asked by ajo
  1. well, find the time for the angular displacement...

    displacement= angularspeed*time find time.

    Then, velocity= distanceapart/time

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    posted by bobpursley
  2. Assume that the two discs are on the same shaft, and that the shaft rotates less than one full rotation as the bullet passes from one disc to the other. The shaft rotates 0.240 rad at 95.0 rad/s during the interval of passing from one to the other. The time required to cover the separation distance is therefore
    t = 0.240/95.0 = __ ? sec.
    Divide d = 0.850 m but t to get the bullet's speed.

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    posted by drwls

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