Question

A juggler is performing an act by juggling several balls. The juggler throws the balls up at an initial height of 3.9 feet with a speed of 14.8 feet per second. If the juggler did not catch a ball, about how long will it take the ball to hit the floor?

1.45 secs

1.14 secs

0.28 secs

0.21 secs



P.S. Equation is
H(t)=-16t^2+vt+s

t=time
v=speed
s=starting height

Answer 1

we meet again agentx5

Answer 2

Acceleration due to gravity (on earth's surface) is still -32.17 ft/s\(^2\) ;-P
( - sign means downward)

Draw a FBD (free-body diagram) first, same as last time, but all you this time.

Answer 3

free body diagram is free hand right?

Answer 4

@ the others:
http://openstudy.com/study#/updates/50044eb5e4b0fb991133b1bc

Yes, a sketch to help you visualize, and a good practice to get into for mechanics problems.

Answer 5

And its the exact same as the other

Answer 6

one

Answer 7

Well except different V\(_0\) (initial speed) and a different initial height (it was zero in the previous problem, now it's +3.9 ft).

Answer 8

ok

Answer 9

Write the units like I did on a piece of scratch paper. These problems are nice because if you're doing it right the units will cancel out and you'll be left in the correct unit for what you were solving for. Again you're solving for t so everything should cancel out so you have seconds. And watch the order of operations! (that's where most people make calculation errors)

Answer 10

Kind of cool that units help you check yourself, you don't get that luxury in most math problems. :D