Question

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

I am sorry, I don't think I know how to solve it. To me, the given condition is not enough to solve.

Answer 2

Hey, can you draw us a picture?

Answer 3

I would conservation of energy.

Define the potential and kinetic energy at the top of the slide and at the bottom. Assuming ideal conditions, the total energy should be conserved.

Recall:

Potential Energy = m * g * h
Kinetic Energy = (1/2) * m * v^2

Answer 4

Yes, conservation of energy would be also easiest in this case. Look at your initial and final conditions and see what you can cancel out, I also want you to draw a picture because it will show that you understand what's going in the problem.

Answer 5

potential energy + kinetic energy is constant

Answer 6

PE + KE = k , where k means just constant.
where
PE = m*g*h
KE = 1/2*m*v^2

at the bottom of the slide we have
m*g*0 + 1/2*m*13^2 = 169/2 * m

Therefor at the top of the slide we must have (let g= 9,81)

m*(9.81)*9 + 1/2*m*v^2 = 169/2 *m

m ( 9.81 * 9 + 1/2 * v^2 ) = 169/2 * m

Answer 7

can you solve for v now?

Answer 8

Here is an easier way to look at it
Initial kinetic energy + initial potential energy = final kinetic energy + final potential energy

Ki + Pi = Kf + Pf

1/2*m*vi^2 + m*g*hi = 1/2mvf^2 + m*g*hf

1/2 *m*vi^2 + m*9.81*9 = 1/2*m(13)^2 + m*g*0

Answer 9

the odd thing about this problem, there is no real solution. its possible whoever made this problem did not work out the math