A discus is released at an angle of 42.0° with respect to the horizontal and a velocity of 28.0m/s.
a)How long does it stay in the air?
b)What horizontal distance does it travel?
Kinetic equation d=Vi*t+ 1/2*at2
Δt=-2Vsinθ / g
The Attempt at a Solution
a) I used Δt=-2Vsinθ / g and solved for Δt=3.82s
b) Used dh=-V2*sin2θ /g to solve for dh= 79.6m
For part b) I don't know when you I am supposed to use dh=-V2*sin2θ /g equation and when I should just use dh=Vh*Δt or the d=Vi*t+ 1/2*at2 equation. If anyone could give me any tricks or explanations of when and why we use that specific equation that would be greatly appreciated. Thank you so much in advance!