Determining how far a body will move up an inclined plane and the time to reach the highest point

[tremain74]

Homework Statement

A body is projected up a 25 degree plane with an initial velocity of 15 m/s. If the coefficient of friction between the body and the plane is 0.25, determine how far the body will move up the plane and the time required to reach the highest point. Answer : 17.7 m, 2.36 s.

Relevant Equations

I tried to use the equation summation of force = p - 0.25N = ma.

15cos25 - 0.25N = ma.

 

[berkeman]

Can you please show all of your work and explain why you are using that approach?

 

[tremain74]

Can you please show all of your work and explain why you are using that approach?

I have tried to used the drawing pad last night to show my work but I am having trouble using it.

 

[berkeman]

Maybe start by talking us through your method...

 

[tremain74]

I have an object that is going up the plane at 25 degrees to the right. It is going at 15 m/s. I drew a free body diagram of the object. I have a P force at 15 m/ s going up the direction at 25 degrees. I also have friction force going in the opposite direction of 0.25 * N.

 

[berkeman]

I have a P force at 15 m/ s going up the direction at 25 degrees.

There is no force up the inclined plane. That 15m/s is the initial velocity up the plane.

You have probably worked through problems where was no frictional force for inclined planes, right? In those cases, you can just use Energy considerations to do the calculation for how far the object makes it up the inclined plane, right? How would you do this is there no friction?

And then, what changes (or additional terms) would you need to include in order to accommodate the frictional force? Does the frictional force back down the inclined plane change with the object's velocity?