Muzzle velocity and distance

Question

A rifle bullet is fired vertically upwards with a muzzle velocity of 700 m/s.  Assuming no air resistance, what height will it reach?  How long will it take to reach the ground again?

Answer 1

Maximum height reached----

 

H=u^2/(2*g)

 

  =700*700/(2*9.8)

 

   =25 km

Time taken to reach maximum height =

 

T= u/g

 

  =700/9.8

 

  =71.4 sec

 

Same time taken to reach the ground.

 

So, total time taken to reach the ground

 

=71.4*2/60

 

=2.38 minutes