If an object is thrown up at an initial velocity of 9.8 m/s, what would be the magnitude of the final velocity upon impact with the ground?
im doing an online class and i don't have a book so if you could explain some of the question that would be great thanks so much
in the absence of other forces than gravity, any object thrown from the ground will return with exactly the same speed
to see this, note that the height h of the missile is
h = 0 + 9.8t - 4.9t^2
= 4.9t(2-t)
the velocity is
v = 9.8-9.8t
= 9.8(1-t)
so, at t=2, v = 9.9(1-2) = -9.8
same speed, opposite direction