Question

22. At what angle with the horizontal should a hunter aim his gun so he will hit a target is 60 meters horizontally away from him, and 20.0 mm above him, if the muzzle velocity of the bullet is 400 m/s?

got 81.4 deg. right?

Answer 1

mm should be in meters i suppose

Answer 2

let angle with horizontal be X
the verticle component of velocity is u*sinX and horizontal componet of velocity is u*cosX.
let after time T it will hit the target then
distance between hunter and target=u*cosX*T
find the value of T from this equation i.e T=60/(u*cosX).
and in the same time it also travelles the vertical distance(distance between target and ground).i.e we apply the basic formula
d=usinX*T-1/2gT^2 put the value of d=20m,u=400 and T=60/u*cosX.
and you get an equation in one variable that variable is X hence after solving it ,get your answer,if u have any problem ,talk to me.