Find Total Force & Direction on Sliding Block | Inclined Plane Help

In summary: This difference is the "total force" (which I would have called the "net force"). Does this help?In summary, the conversation discusses a problem involving a block sliding down a plane at an angle of 37 degrees with a coefficient of kinetic friction of 0.20. The goal is to determine the 2-letter combination for the total force on the block and the direction of the force on the ramp due to the sliding block. The conversation discusses drawing a diagram and using trigonometry to understand the forces acting on the block. The total force is determined by calculating the difference between the force of friction and the component of gravity along the plane.
  • #1
collegegirl13
6
0
http://i98.photobucket.com/albums/l263/Rampalski/randomlabel.png

Using that picture above and this data... A block of mass M slides down a plane at an angle of 37o to the horizontal. The coefficient of kinetic friction = 0.20. The horizontal lines in the picture represent magnitude of forces, in units of the force of gravity on the block. The arrows show directions for forces. DATA: sin(37o)=0.60 cos(37o)=0.80, tan(37o)=0.75. I need to find

A)The 2-letter combination for the total force on the block.
B)The direction of the force on the ramp due to the sliding block. If it is along one of the arrows, select that arrow. If not, select the two adjacent arrows between which that force is directed.



I have no clue what to do or what equation to use...
 
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  • #2
collegegirl13 said:
http://i98.photobucket.com/albums/l263/Rampalski/randomlabel.png

Using that picture above and this data... A block of mass M slides down a plane at an angle of 37o to the horizontal. The coefficient of kinetic friction = 0.20. The horizontal lines in the picture represent magnitude of forces, in units of the force of gravity on the block. The arrows show directions for forces. DATA: sin(37o)=0.60 cos(37o)=0.80, tan(37o)=0.75. I need to find

A)The 2-letter combination for the total force on the block.
B)The direction of the force on the ramp due to the sliding block. If it is along one of the arrows, select that arrow. If not, select the two adjacent arrows between which that force is directed.



I have no clue what to do or what equation to use...

Your first job is to draw a nice neat picture. The purpose of this is to understand what's happening. Draw an x-axis parallel to the plane and a y-axis perpendicular to it. Put the origin in the center of the block. Now draw some arrows representing the forces. One vertical representing gravity down. Notice that gravity acts to accelerate the block down the plane and also acts to hold the block onto the plane. Draw in arrows to represent these two components of the force of gravity. Draw in an arrow to represent the force of the plane on the block. Notice that this is equal and opposite to the force of gravity holding the block on the plane. Is friction a part of your problem? If it is it will act up the plane.
The force of gravity on your block is mg. You will have to use some trigonometry to figure out the component of gravity down the plane and the component of gravity perpendicular to the plane.

That should get you started. Remember: the first step is not to find an equation. The first step is to understand what's happening.
 
  • #3
I already did all that I don't understand how I figure out the total force do you add everything up or what??
 
  • #4
Often people get confused by problems with just a variable for the mass. If "m" throws you off for mass, go ahead and plug in 10 kg, 50 kg, or whatever number turns you on. Then when you've solved it, just divide by that number to get the value in terms of "m".

If the style of the answers to the problem is giving you troubles: The two letters refer to one to match the angle, and another to match the length of the vector.

Hope this helps. This problem is a fairly straight-forward one; use the tips AEM offered. "Total force" is just that, the vector addition of the forces. Remember that some of them will cancel each other out.
 
  • #5
collegegirl13 said:
I already did all that I don't understand how I figure out the total force do you add everything up or what??

Well, I agree that the request for the "total force" is confusing. If I were writing the problem, I wouldn't have worded it that way. So let's take the problem apart. The force of gravity holding the block on to the plane is balanced by the force of the plane on the block, so there's no motion in the y direction (the direction perpendicular to the plane). Along the plane you have the component of gravity acting down the plane and the force of friction up the plane. The force of friction is given by the coefficient of friction time the normal force (that's the force holding the block onto the plane). If the component of the force of gravity along the plane is larger than the force of friction the block moves. So you need to compute the difference between this frictional force and the component of gravity acting down the plane. I'll bet this difference is what the person writing the problem had in mind.
 

1. How do you calculate the total force on a sliding block on an inclined plane?

The total force on a sliding block on an inclined plane can be calculated using the formula F = mgsinθ, where F is the total force, m is the mass of the block, g is the acceleration due to gravity, and θ is the angle of the incline.

2. What direction does the total force act on the sliding block?

The total force on the sliding block acts in the direction of the incline. This means that the force is parallel to the surface of the incline and points downward if the incline is angled downward, and upward if the incline is angled upward.

3. How does the mass of the block affect the total force?

The mass of the block directly affects the total force, as shown in the formula F = mgsinθ. The greater the mass of the block, the greater the total force will be.

4. Can the angle of the incline affect the total force on the sliding block?

Yes, the angle of the incline can affect the total force on the sliding block. As the angle increases, the total force will also increase. This is because the component of gravity acting parallel to the incline will become larger as the angle increases.

5. How can you determine the direction of the total force on a sliding block on an inclined plane?

The direction of the total force on a sliding block on an inclined plane can be determined by the direction of the incline. If the incline is angled upward, the total force will act in an upward direction, and if the incline is angled downward, the total force will act in a downward direction.

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