will somebody help me with my homework?

A body slides down in a frictionless plane during the third second after starting from rest it travels 19.4 meters. What is the angle of the plane?

Thanks in advance

Question

will somebody help me with my homework?

A body slides down in a frictionless plane during the third second after starting from rest it travels 19.4 meters. What is the angle of the plane?

Thanks in advance

anonymous · Answer

x= 0.5 g t^2

science0229 · Answer

|dw:1407057873069:dw|

anonymous · Answer

oh i forgot to put sin theta in my equation.

science0229 · Answer

Since it took 3 seconds to travel 19.4 meters, its final velocity is 19.4/3
Its initial velocity is 0, of course, since it was at rest, first.

science0229 · Answer

@Careless

science0229 · Answer

Using the work-energy theorem...$$Work=(Force)(Distance)=\Delta (Kinetic Energy)=\frac{ 1 }{ 2 }m {v _{f}}^2-\frac{ 1 }{ 2 }m {v _{i}}^2$$

science0229 · Answer

vf is the final velocity, which is 19.4/3
vi is the initial velocity, which is 0
Distance is 19.4

science0229 · Answer

Force is as following|dw:1407058991396:dw|

science0229 · Answer

I'm guessing that you're using 9.8 for the gravitational acceleration (of Earth)

science0229 · Answer

since we're on the inclined plane, the force would be $$9.8m \sin \theta$$

science0229 · Answer

Substitute all of that in the work-energy theorem

science0229 · Answer

$$9.8m \sin \theta*19.4=\frac{ 1 }{ 2 }m (\frac{ 19.4 }{ 3 })^2$$

science0229 · Answer

Solve for sin to get$$\sin \theta=\frac{ 97 }{ 882 }$$

science0229 · Answer

You can solve for theta on your own.

science0229 · Answer

If the gravitational acceleration is 'g', then the final equation would turn out as$$\sin \theta=\frac{ 97 }{ 90g }$$

science0229 · Answer

This turned out ugly...

science0229 · Answer

@Catch.me 
Did I do something wrong?
When the answer comes out like this, I always have a feeling that I made a mistake somewhere

anonymous · Answer

I didn't follow ,but the main idea is right (don't mind about small errors you just give the keys to answer it :D)

science0229 · Answer

I guess so :)

anonymous · Answer

thank you :)

anonymous · Answer

an arrow is shot vertically upward with a speed of 288 fps and 3 seconds later another arrow is shot up with a speed of 244 fps. will they meet? if so, where?

anonymous · Answer

please answer this another question :)

anonymous · Answer

Hey show your work and why can't solve it?

anonymous · Answer

after i have finish my homework i will show my solution ok? I'm sorry because i am very busy right now. We have midterm this week. so stay still. until i show my solution. Thank you for understanding.