Solving Friction and Net Force Problems

In summary, it takes 500 Newtons to keep the object moving at a constant velocity, and the net force required to stop the object in 8 seconds is 400 kg m/s.
  • #1
flowerchild
2
0
Help Me Please!

You don't have to actually do this, but does anyone know how to so I can solve it myself?
:confused::rolleyes:

1) A 50 Newton horizontal force is needed to keep an object weighing 500 Newtons moving at a constant velocity of 2.0 m/s across a horizontal surface. What is the magnitude of the frictional force acting on the object?

2) A 40 kg mass is moving across a horizontal surface at 5 m/s. What is the magnitude of the net force required to bring the mass to a stop in 8 seconds?


PLEASE HELP! Thanks!
 
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  • #2
1) draw a free body diagram. and the frictional force is equal to the coeffecient of friction times the Normal force.

2) draw free body diagram, us the equation of motion as well as Newtons 2nd law.
 
  • #3
How do you find coefficient of friction and what is the equation of motion?
 
  • #4
coefficient of friction is usually a given in a problem, is is an intrinsic property that relates the interaction between two surfaces rubbing up against each other. F=ma is the equation of motion, knowing this and that the change in position (∆x) is equal to the change in time (∆t) times the given velocity. where the ∆x is final position minus the initial position, will help in solving the problem. I made an error in my previous post about the definition "Equation of motion" so ignore it.
 
  • #5
flowerchild said:
You don't have to actually do this, but does anyone know how to so I can solve it myself?
:confused::rolleyes:

1) A 50 Newton horizontal force is needed to keep an object weighing 500 Newtons moving at a constant velocity of 2.0 m/s across a horizontal surface. What is the magnitude of the frictional force acting on the object?

2) A 40 kg mass is moving across a horizontal surface at 5 m/s. What is the magnitude of the net force required to bring the mass to a stop in 8 seconds?


PLEASE HELP! Thanks!

1) Divide out to find how many Newtons it takes to move at 2.0 m/s and then solve. (Assuming the answer for the coefficient of friction is to be given in N m/s)

2) So, the object has a net inertia of 200 kg m/s and you need to stop it in 8 seconds. Is the net force any different if you need to stop it in 2hrs? or 1 second? I don't think so, but I suspect the question actually asks what is the net force in kg m/s. This is a case of units matter. Please clarify.
 

Related to Solving Friction and Net Force Problems

1. What is friction and how does it affect motion?

Friction is a force that opposes the relative motion between two surfaces in contact with each other. It can either slow down or stop an object's motion, or cause it to change direction. It is caused by the microscopic irregularities on the surface of objects and is affected by factors such as the type of surfaces, the force pressing the surfaces together, and the roughness of the surfaces.

2. How do you calculate the force of friction?

The force of friction can be calculated using the formula Ff = μN, where Ff is the force of friction, μ is the coefficient of friction, and N is the normal force. The coefficient of friction is a constant value that depends on the type of surfaces in contact, while the normal force is the perpendicular force exerted by one surface on the other.

3. What is net force and how do you determine its direction?

Net force is the overall force acting on an object, taking into account all the individual forces acting on it. In order to determine its direction, you have to consider the direction of each individual force and add them together. If the forces are acting in opposite directions, you subtract them to find the net force. The direction of the net force is the same as the direction of the resulting force.

4. How do you solve net force problems involving multiple forces?

To solve net force problems involving multiple forces, you first have to draw a free body diagram, which is a visual representation of all the forces acting on the object. Then, you can use the equations F = ma and ΣF = ma to find the net force and acceleration of the object. It is important to pay attention to the direction of the forces and use positive and negative signs accordingly.

5. How can you reduce friction in a system?

Friction can be reduced by using lubricants, such as oil or grease, between two surfaces to create a smoother surface and reduce the contact between them. Another way is by using materials with lower coefficients of friction, such as Teflon or graphite. Additionally, reducing the weight or force pressing the surfaces together can also decrease friction.

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