A sled is initially given a shove up a friction-less 31.0 degree incline. It reaches a maximum vertical height 1.55m higher than where it started. What was its initial speed?
I found mgcos31=fn and mgsin31=ma and then set them equal to each other and canceled out mass but im stuck there.

Question

A sled is initially given a shove up a friction-less 31.0 degree incline. It reaches a maximum vertical height 1.55m higher than where it started. What was its initial speed?
I found mgcos31=fn and mgsin31=ma and then set them equal to each other and canceled out mass but im stuck there.

anonymous · Answer

Use kinematics' equations for the other data given.

anonymous · Answer

you can apply that in component form in the vertical direction. Once you get the vertical component of velocity you can easily get the complete velocity.

anonymous · Answer

Is mgcos31 the y component and mgsin31 the x component

anonymous · Answer

this will depend on what you chose as the axes.

anonymous · Answer

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anonymous · Answer

I got it thanks.  I used the conservation of energy.  I set 1/2mv2 =mgdelta*height

anonymous · Answer

That's cool.  But still kinematics can be applied here too. I'm sure you must have studied those kinematics equations.