Block sliding down ramp, energy problem

[Chrisleo13]

Homework Statement

A 1.79-kg block slides down a frictionless ramp, as shown in the figure below.


The top of the ramp is h1 = 1.54 m above the ground; the bottom of the ramp is h2 = 0.287 m above the ground. The block leaves the ramp moving horizontally, and lands a horizontal distance away. Calculate the distance .

Homework Equations

1/2mv^2

The Attempt at a Solution

I'm lost.

 

[Rake-MC]

The figure is not shown, however I can give you this advice.

$$U_g = mg\Delta h$$

and $$E_k = \frac{1}{2}mv^2$$

Initially kinetic energy = 0, all energy is gravitational. Let the two equations equal each other to solve for v.

Then use constant acceleration formulae to find distance

 

[Chrisleo13]

http://www.webassign.net/walker/08-25alt ...

There is the figure, sorry I forgot to post it.

 

[Rake-MC]

http://www.webassign.net/walker/08-25alt ...

There is the figure, sorry I forgot to post it.

It says 'no page found'

If you follow my instructions it should work out.

 

[Chrisleo13]

I found v easily, but I don't have an acceleration or a time to find distance traveled.

 

[Rake-MC]

Well you do, you just have to think about it.
There is no force in the x plane once it has left the ramp, therefore velocity is constant.
The acceleration in the y plane will be 9.81N (due to gravity)
The distance it will fall in the y plane is 0.287m (the distance from bottom of ramp to ground).
and the initial y velocity is zero (it specifies it is initially traveling horizontally).

This is all the information you need.

 

[Chrisleo13]

I'm sorry this isn't making sense to me for some reason, do you find time with that information given. I am trying to find the distance traveled in the x direction correct?

 

[Rake-MC]

Yes that's correct. You have velocity, and you want distance, in order to calculate this, you need time.

You can calculate (using the parameters I defined in my previous post) the time it takes for it to fall to the ground. That will be the same time you will use to calculate your final answer.

HINT: $$s = ut + \frac{1}{2}at^2$$

where s = displacement
u = initial velocity
t = time
a = acceleration

 

[Chrisleo13]

Thanks for your help, but I am still getting the answer incorrect. I did all what you said


vfx = 4.96
t = .242
vix = 0
xi = 0
xf = ?

Right?