Question

Is this question possible to solve?: While at Magic Springs, Katie goes down a frictionless water slide that is 9.0 m above the ground. At the bottom of the slide, Katie reaches a final speed of 13 m/s. What was Katie's initial speed when she pushed off the top of the slide?

Answer 1

No, it can be done. use energy conservation to set up equations. pretty basic stuff

Answer 2

Well you can't really solve it without mass

Answer 3

but mass cancels right

Answer 4

how

Answer 5

\[\frac{ 1 }{ 2 }mv _{i} ^{2}+mgh=\frac{ 1 }{ 2 }mv _{f} ^{2}\]

Answer 6

since m is non-zero, you can divide m on both sides

Answer 7

there is really nothing tricky

Answer 8

I got for \[v _{i}\] = 1.36m/s

Answer 9

well, change against the official answer

Answer 10

what do you mean

Answer 11

I mean is the answer given to you? like at the back of the book or somewhere?

Answer 12

not it's a worksheet and I solved it and I think it's right???

Answer 13

@caozeyuan

1/2mvi^2 + mghi = 1/2mvf^2 + mghf
1/2mvi^2 + m(9.8)(9) = 1/2m(13^2) + m(9.8)(0)
1/2vi^2 + 88.2 = 84.5 + 0
0.5vi^2 = 3.7
vi^2 = 1.85
vi = 1.36 m/s

Answer 14

this IS impossible to solve

Answer 15

not because of the mass but becuase of the negative sign

Answer 16

your vi is an imaginary number, therefore the speed don't exist

Answer 17

I'll talk to my teacher about it, because he wrote it

Answer 18

Yea, this is really werid

Answer 19

I am sorry about the confusion, he's confusing sometimes