Homework help? [ block on inclined plane ]

[myaaxcore]

Homework help?? [ block on inclined plane ]

Homework Statement

002 (part 1 of 3) 10.0 points
A 3.86 kg block slides down a smooth, fric-
tionless plane having an inclination of 28◦ .
The acceleration of gravity is 9.8 m/s2 .
Find the acceleration of the block.
Answer in units of m/s2.

003 (part 2 of 3) 10.0 points
What is the block’s speed when, starting from
rest, it has traveled a distance of 2.35 m along
the incline.
Answer in units of m/s.

004 (part 3 of 3) 10.0 points
What is the magnitude of the perpendicular
force that the block exerts on the surface of
the plane at a distance of 2.35 m down the
incline?
Answer in units of N.

 

[denverdoc]

We are here to help myaxx... but can't do it for you. You need to throw up some equations and say why you are stuck.

 

[myaaxcore]

i don't know what equations to use.
i just need the equations for each problem. i can get the answer myself :]

 

[denverdoc]

OK, but if this is for a class, you should either have a chapter or notes or something to use as a reference.

The first problem is best understood by use of a free body diagram, illustrating all the forces acting on the block. In this case only a portion of the force of gravity is available to pull the block down the slope. It is related to the trig of the situation.

The second is a problem in kinematics. You should somewhere have reference to equations which relate distance to either velocity and/or acceleration.

The third part deals with the force the block exerts on the plane and again can be found by consideration of the free body diagram. Does any of this ring a bell?