Projectile Motion 1

Question

A bird flying horizontally accidentally drops a rock it was carrying. 2.10s later, the rock’s velocity is 22.2 m/s in a -68.2 degree direction. What was the bird’s (and rock’s) initial velocity? (Hint: the rock was originally moving with the bird)

Answer 1

Let v= v_0y -gt and v_0y = v₀ sin 68.2° so 22.2m/s = v₀ sin68.2° -9.8•2.1 = v₀ (.928) - 20.58 m/s solving for v₀ gives v₀ =( 22.2 + 20.58 )/ .928 and v₀ = 46.08m/s which is the initial velocity of the bird and the rock.