Question

If a ball that is freely falling has attained a velocity of 19.6 m/s after two seconds, what is its velocity five seconds later?

Answer 1

t=19.6/2
v=5 * 9.8
=49 m/s

Answer 2

Nope. Sorry J.
7*9.8=68.6

Answer 3

@Chanz, oops my bad, you are correct.
Vf-19.6 m/s= (9.8 m/s/s)(5 s)
Vf-19.6 m/s = 49 m/s
Vf= 68.6 m/s

Answer 4

forgot that last calculation :)

Answer 5

wait so i did 9.8 times 5 and got 49, is that the final answer? and how did you guys get 68.6 and what does that number mean?

Answer 6

nope, you forgot acceleration (a)
a=vf (final velocity) - vi (initial velocity) divided by t (time)
the acceleration of a free falling body is 9.8 m/s/s due to the force of gravity.
9.8 m/s/s=vf-19.6m/s / 7s
if you multiply both sides by 7, you get
68.6 m/s/s=vf-19.6 m/s
then you add 19.6 to both sides and you get
88.2 m/s/s= vf
so the final velocity (the answer) is equal to 88.2 m/s/s

correct me if I'm wrong but I think that's how you do it