Newton's Laws Finding Applied Force and other Forces

In summary, Sean, who has a mass of 50 kg, is skiing on a patch of snow with a coefficient of friction of 0.20. Using the equation F=ma and the given information, we can find that the force of friction (Ff) is 98.1 N. However, we still need to find the force applied and the sum of forces in order to solve for acceleration. We can use the equations Fgravity = 490.5 and Ffric = μmg to find the force applied and the horizontal acceleration, respectively. Remember to only plug values into equations with a good reason and keep in mind that the vertical acceleration is zero.
  • #1
jackilynn
1
0
1. Sean the skier is headed for a rough patch of snow with the coeffcient of friction 0.20. Find his acceleration if his mass is 50 kg.
2. F=ma, coeffcient of friction=Ff/Fn
3. Fgravity = 490.5 using the equation coeffcient of friction=Ff/Fn we get 0.20 = Ff/490.5 which equals Ff = 98.1
This is where i get stuck. i do not know how to find the Force applied to use it to find the sum of the two forces (force applied and force of friction) to plug into the equation F= ma.
 
Physics news on Phys.org
  • #2
The sum of forces equals ma (Newtons 2nd law). Use it to write down the equation(s) to be solved.
You know that the vertical acceleation is zero:
[itex]0= N - mg\\
F_{fric} = \mu N=\mu mg\\
\sum F_{horizontal} = ma = -F_{fric}[/itex]
So never plug into any equation unless you have a good reason
 

1. What are Newton's laws of motion?

Newton's laws of motion are three fundamental principles that describe the behavior of objects in motion. The first law states that an object at rest will remain at rest, and an object in motion will remain in motion at a constant velocity, unless acted upon by an external force. The second law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. The third law states that for every action, there is an equal and opposite reaction.

2. How do Newton's laws help us find applied force?

Newton's second law, also known as the law of acceleration, states that the net force acting on an object is equal to the mass of the object multiplied by its acceleration. So, if we know the mass and acceleration of an object, we can use this formula to calculate the applied force.

3. What is the difference between applied force and other forces?

Applied force is a specific type of force that is applied by an external agent on an object. Other forces, such as gravitational force, frictional force, and normal force, may also act on an object, but they are not applied forces because they are not directly caused by an external agent.

4. How can we apply Newton's laws to real-life situations?

Newton's laws can be applied to a wide range of real-life situations, from the motion of planets in space to the movement of a car on a road. For example, understanding Newton's second law allows engineers to design cars with the right amount of force to accelerate and brake safely. Additionally, Newton's third law can be seen in action when a rocket launches into space, as the force of the rocket pushing down on the ground is equal and opposite to the force of the ground pushing up on the rocket.

5. What are some common misconceptions about Newton's laws?

One common misconception is that Newton's first law only applies to objects at rest or in motion in a straight line. In reality, it also applies to objects in circular motion, as they are constantly changing direction. Another misconception is that an object must be at rest for Newton's second law to apply. However, the law applies to objects in motion as well, as long as there is a net force acting on the object. Finally, some people believe that Newton's third law means that forces always cancel each other out, but this is not true as the forces act on different objects and have different effects.

Similar threads

Coefficient of kinetic friction of a block sliding across the ceiling
    • Introductory Physics Homework Help
Replies
7
Views
329
Calculating Net Force and Friction: Understanding Newton's Laws of Motion
    • Introductory Physics Homework Help
Replies
9
Views
2K
Newton's law problem: Pushing 2 stacked blocks on a horizontal table
    • Introductory Physics Homework Help
Replies
13
Views
938
For the friction formula when to use Fn(normal force)×mu and when F×mu
    • Introductory Physics Homework Help
Replies
17
Views
591
Feynman's Lectures exercise about Newton's laws
    • Introductory Physics Homework Help
Replies
13
Views
529
Finding Radial Force from Free Body Diagram
    • Introductory Physics Homework Help
Replies
4
Views
1K
Maximum force applied to prevent block from sliding up ramp
    • Introductory Physics Homework Help
Replies
11
Views
1K
Newton's 2nd Law: Why is Resistance Considered a Positive Force?
    • Introductory Physics Homework Help
Replies
3
Views
950
Coefficient of Friction when Normal Force is Reduced [HS]
    • Introductory Physics Homework Help
Replies
5
Views
1K
Two forces acting on an object given in vectors - SOLVED
    • Introductory Physics Homework Help
Replies
1
Views
662

Hot Threads

Recent Insights

Back
Top