At time t = 0, you shoot a cannonball horizontally from the roof of a building at a velocity of 10 m/s. The building has a height of 80 m. Assume g = 10 m/s2 and that there is no air resistance.

Question

Write down the algebraic velocity equation for the y-direction of the ball with any given values substituted.

Write down the algebraic position equation for the y-direction of the ball with any given values substituted.

So I need to equations for vertical velocity (Vy) and vertical position (y)

Answer 1

v(y) =gt
y=gt²/2.

h= gt²/2 =>
t=sqrt(2h/g)= sqrt(2•80/10)=4 s.

v(y) =gt =10•4 =40 m/s (near the ground)