How do I calculate the bullet’s speed in m/s?
A pellet is fired through two circular plates .8 m apart, both rotating at -95rad/s. The angular displacement of second bullet hole is 82° from the first bullet hole. Calculate the bullet’s speed in m/s.
A pellet is fired through two circular plates .8 m apart, both rotating at -95rad/s. The angular displacement of second bullet hole is 82° from the first bullet hole. Calculate the bullet’s speed in m/s.
1 Answer
Feb 23, 2018
Time taken by the bullet from one plate to second is equal to time taken by the plates to rotate through the given angle
- Let
#v# be the velocity of the bullet.
Time taken to travel a distance of#0.8\ m=0.8/v\ s# .......(1) - We know that
#pi\ rad=180^@# . Ignoring the#-ve# sign of rotating speed as it indicates the direction of measurement of angle,#95\ rad\ s^-1=95/pixx180^@#
Time taken to rotate through given angle of#82^@#
#=1/(95/pixx180)xx82\ s# #=0.033\ s# ........(2)
Equating (1) and (2) we get
#0.8/v=0.033#
#=>v=>0.8/0.033=24.2\ ms^-1#
