Solving Physics Problem: Find Distance up Incline (Grade 11)

[RebWal]

I don't know how to solve for s. The question is How far up the incline will the block slide, and I was to solve it 2 ways.

I think I got the first way, and this is what I have so far for the 2nd way.

w=e2-e1
-Ff*s=e2-e1
-Moo g Cos pheta*s=1/2v^2-gh
-.21(9.8)Cos38*s=1/2(5.75)^2-9.8[s(Sin38)]

I'm not sure how to solve for s. If anyone could help me out I'd really appreciate it.

Oh by the way, this is grade 11 physics, and the first way I did it was using Fnet=ma and substituting a into v2^2=v1^2+2as and I got s=14m -- Not positive if that is right

 

[geoffjb]

I don't know how to solve for s. The question is How far up the incline will the block slide, and I was to solve it 2 ways.

I think I got the first way, and this is what I have so far for the 2nd way.

w=e2-e1
-Ff*s=e2-e1
-Moo g Cos pheta*s=1/2v^2-gh
-.21(9.8)Cos38*s=1/2(5.75)^2-9.8[s(Sin38)]

I'm not sure how to solve for s. If anyone could help me out I'd really appreciate it.

Oh by the way, this is grade 11 physics, and the first way I did it was using Fnet=ma and substituting a into v2^2=v1^2+2as and I got s=14m -- Not positive if that is right

Although it's great that you included your work, the question would be nice, too.

 

[RebWal]

I included the question. It is: How far up the incline will the block slide? The block is 3.3kg, and the angle of incline is 38 degrees. Coefficient of friction is .21 and the speed is 5.75 m/s

 

[student85]

You can solve the problem using the principle of the conservation of mechanical energy. The Kinethic energy in t=0 has to be equal to the potential energy it its maximum height plus the energy it lost due to friction which is ( (Coef. of fric.)(Normal)(distance travelled) ). You get its max. height using trigonometry you know that sen38 = height/distance travelled. there you go.