Friction
What I learned:
*Ways to find friction:
->If an object has balanced forces (it is either not moving or has a constant velocity), that means the force opposite to the force of friction is the same as the force of friction. (A car is moving constantly on the road. For the vertical forces, the downward force of the Earth and the upward force of the road are balanced. For the horizontal forces, the force of the car in the direction that it is traveling is ___Newtons. That means the force of friction in the opposite direction is the same amount of Newtons too.)
->If an object does not have balanced forces (it is accelerating), then one can use sin/cos/tan to solve for the force of the friction. (Some variables you might need are the quantitative forces of the other vectors and/or the angle of the forces if it is diagonal.)
*Surface area, speed and shape DO NOT AFFECT the force of friction
*The type of material and mass AFFECT the force of friction
*For my group experiment, my members and I chose to do it on material and shape.
->For the material experiment, my members and got blocks with different materials on each surface. For example, one block had a plastic side on one of its surfaces, another was marble, one was cork, and the last one was felt. We made sure all the blocks were the same weights by adding small weights to some blocks that weighed less to even all of them out. Next, we connected the block to a force-o-meter and the force-o-meter to a buggy with string. We chose a buggy because we knew that that would be moving at a constant speed. We connect each block to the force-o-meter and started the buggy. We timed it to see how long it would take for the block to move 10 tiles. Of course, all the forces were balanced because it was moving constantly and we found out the force of friction by finding the force of the buggy that was moving the block by looking at the force-o-meter, since they are equal. We found out that the material does have an effect on the friction. Materials with a smoother surface do not have as much friction acting on it as materials with a rougher surface.
->For the shape experiment, we had styrofoam cutouts of a circle, a square and a triangle. All of them were the same material, had the same mass, surface area, and were moving at a constant speed (again, using the buggy). For this experiment, we did the same procedure as the material experiment. The only difference was that we had to add a small weight on all the shapes just to increase the weight because the styrofoam was too light to be read on the force-o-meter. Again, all the forces were balanced and we were able to figure out the force of friction by reading the force at which the buggy pulled the styrofoam from the force-o-meter. By keeping the material, mass, surface area, and speed constant, we were able to find out that shape does not the force of friction because for each shape, the force of friction was the same.
*Friction is the force opposing the force of movement. It goes against the force of the movement in the opposite direction.
*Force Friction= (μ)(Force Normal)
*Fun fact: Ever wondered why snow shoes are like tennis rackets and have such a big surface area? It is because when one wears regular shoes, all the weight is concentrated on where the person is standing, and if that person is on snow, then he or she would sink down into the snow. However, if the person wears snow shoes with the bigger surface area, the weight of the person is concentrated over a bigger area and that person would not sink down into the snow as much. How convenient!
Questions:
*What is friction actually? We think of forces as objects. For example, in the situation of a car moving constantly on a flat ground, force Earth is the force of the Earth pulling the car down and force ground is the force of the ground pushing the car up. If this is the case, then what is the "object" that causes friction? Is it the actual car in the situation or some other object?
*What can μ represent in Force Friction= (μ)(Force Normal)?
*When we do a force diagram, do we have to label force Earth and force friction in the negative? Or do we label it for only force Earth? Or do we keep the forces on the force diagram all positive but when we try to find the net force, that is when we put in the negatives? Is moving left or going down always considered negative and moving right or going up always considered positive?
Reflection (and questions):
*When it comes to force friction, I understand how to do the math, but what I do not understand is the actual concept of friction. What is it? Why is it here? Is it something tangible? Where does it come from? I know that it is an opposing force to the force of movement. I know that when two surfaces slide past each other, there is friction. Does friction have anything to do with energy? Is there friction when two objects just touch and there is no movement? (I do not think so. Think about a car that is resting still on a flat road. The car is touching the road and the road is touching the car. There is no movement. That means there is no friction too. When a force diagram is drawn for this situation, there is no force friction.) What is force friction? Other than that, I'm fine with the rest of the concepts on friction.
*Ways to find friction:
->If an object has balanced forces (it is either not moving or has a constant velocity), that means the force opposite to the force of friction is the same as the force of friction. (A car is moving constantly on the road. For the vertical forces, the downward force of the Earth and the upward force of the road are balanced. For the horizontal forces, the force of the car in the direction that it is traveling is ___Newtons. That means the force of friction in the opposite direction is the same amount of Newtons too.)
->If an object does not have balanced forces (it is accelerating), then one can use sin/cos/tan to solve for the force of the friction. (Some variables you might need are the quantitative forces of the other vectors and/or the angle of the forces if it is diagonal.)
*Surface area, speed and shape DO NOT AFFECT the force of friction
*The type of material and mass AFFECT the force of friction
*For my group experiment, my members and I chose to do it on material and shape.
->For the material experiment, my members and got blocks with different materials on each surface. For example, one block had a plastic side on one of its surfaces, another was marble, one was cork, and the last one was felt. We made sure all the blocks were the same weights by adding small weights to some blocks that weighed less to even all of them out. Next, we connected the block to a force-o-meter and the force-o-meter to a buggy with string. We chose a buggy because we knew that that would be moving at a constant speed. We connect each block to the force-o-meter and started the buggy. We timed it to see how long it would take for the block to move 10 tiles. Of course, all the forces were balanced because it was moving constantly and we found out the force of friction by finding the force of the buggy that was moving the block by looking at the force-o-meter, since they are equal. We found out that the material does have an effect on the friction. Materials with a smoother surface do not have as much friction acting on it as materials with a rougher surface.
->For the shape experiment, we had styrofoam cutouts of a circle, a square and a triangle. All of them were the same material, had the same mass, surface area, and were moving at a constant speed (again, using the buggy). For this experiment, we did the same procedure as the material experiment. The only difference was that we had to add a small weight on all the shapes just to increase the weight because the styrofoam was too light to be read on the force-o-meter. Again, all the forces were balanced and we were able to figure out the force of friction by reading the force at which the buggy pulled the styrofoam from the force-o-meter. By keeping the material, mass, surface area, and speed constant, we were able to find out that shape does not the force of friction because for each shape, the force of friction was the same.
*Friction is the force opposing the force of movement. It goes against the force of the movement in the opposite direction.
*Force Friction= (μ)(Force Normal)
*Fun fact: Ever wondered why snow shoes are like tennis rackets and have such a big surface area? It is because when one wears regular shoes, all the weight is concentrated on where the person is standing, and if that person is on snow, then he or she would sink down into the snow. However, if the person wears snow shoes with the bigger surface area, the weight of the person is concentrated over a bigger area and that person would not sink down into the snow as much. How convenient!
Questions:
*What is friction actually? We think of forces as objects. For example, in the situation of a car moving constantly on a flat ground, force Earth is the force of the Earth pulling the car down and force ground is the force of the ground pushing the car up. If this is the case, then what is the "object" that causes friction? Is it the actual car in the situation or some other object?
*What can μ represent in Force Friction= (μ)(Force Normal)?
*When we do a force diagram, do we have to label force Earth and force friction in the negative? Or do we label it for only force Earth? Or do we keep the forces on the force diagram all positive but when we try to find the net force, that is when we put in the negatives? Is moving left or going down always considered negative and moving right or going up always considered positive?
Reflection (and questions):
*When it comes to force friction, I understand how to do the math, but what I do not understand is the actual concept of friction. What is it? Why is it here? Is it something tangible? Where does it come from? I know that it is an opposing force to the force of movement. I know that when two surfaces slide past each other, there is friction. Does friction have anything to do with energy? Is there friction when two objects just touch and there is no movement? (I do not think so. Think about a car that is resting still on a flat road. The car is touching the road and the road is touching the car. There is no movement. That means there is no friction too. When a force diagram is drawn for this situation, there is no force friction.) What is force friction? Other than that, I'm fine with the rest of the concepts on friction.
Comments
Post a Comment