Pulling an object with a rope

1. Sep 22, 2009

Nal101

1. The problem statement, all variables and given/known data

1) What is the net force on the block? (Cartesian Coordinate system)
2) What is the X component of the tension force on the block
3) What is the x-component of the force exerted by the floor on the block (the friction force)?
4) What is the y-component of the force exerted by the rope on the block?
5) What is the y-component of the force exerted by the Earth on the block?
6) What is the y-component of the force exerted by the floor on the block (sometimes called the "normal" force, because it is perpendicular to the floor)?

I pull on the rope with the force of 290 N
Mass of block is 22kg
Block moves at constant 1.3m/s
Angle of 35 degrees with the floor.

2. Relevant equations
p=mv
$$\Delta$$p=fnet$$\Delta$$t
ma = T - W
Ff = $$\mu$$N

3. The attempt at a solution
1) The net force will be the total force acting on the block, therefore in the X direction it would include the X component of the force I exert, and the Y component of the force I exert minus the force of gravity acting on the object.
Fx, me = 290 N * cos(35) = 237.55
Fy, me = 290 N * sin(35) = 166.34
Fgravity = mg = 215.6
Therefore <237.55, (166.34-215.6), 0>

2) Velocity is constant, so no acceleration, therefore T = W. Therefore, I dont know where to go with this.

3) I do not know mu, dont know how to solve for the force of friction.

4) Would this be equal to the force I exert on the rope multiplied by the sin of 35?
290sin(35) = 166.34

5) Already calculated this as well, Fg = mg = 215.6

6) Equal and opposite of Fg?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited: Sep 22, 2009
2. Sep 22, 2009

kuruman

For question 1
What is the acceleration of the block?
How is the acceleration of the block related to the net force acting on it?

Once you get the answer to question 1 sorted out the rest should be easier to handle.

Clarification
Your problem statement does not give the mass of the block. What is it?

3. Sep 22, 2009

Nal101

For question 1) Thanks! Of course, the net force is going to be 0 if there is no acceleration.

For mass of object, had a typo, what was originally mass of rope should be mass of block (22kg) the mass of rope/myself is supposed to be negligible, i apologize.

Figured out 2.

For 3, how do I calculate Ff without knowing $$\mu$$?

Figured out 4 & 5

For 6, is it the sum of earth + rope forces, multiplied by 1 (since its opposite direction)?

4. Sep 22, 2009

kuruman

The sum of the horizontal components of the net force must be zero. Just balance the forces. "To the right" is positive, "to the left" is negative.

Figured out 4 & 5

The sum of the vertical components of the net force must be zero. "Up" is positive, "down" is negative.