How Can I Calculate the Kinetic Friction Between Plastic and Cardboard?

In summary, the conversation is about trying to figure out the force of a Tonka truck moving at a constant velocity on a cardboard bridge. The equation F=ma+muK*fn is used to find the force, but since there is no acceleration in the Y direction, fn equals the weight. The conversation also discusses how velocity and force are two different things and cannot be converted. Furthermore, if the truck is moving at constant velocity and the wheels are rolling, the net force is zero and kinetic friction does not apply. The conversation also suggests finding the driving force using the power output of the motor and velocity.
  • #1
NutriGrainKiller
62
0
Working out some simple physics and I can't figure out how to convert velocity to Newtons for force..

A six pound (2.72kg) tonka truck is moving across a cardboard bridge at a constant velocity of .067m/s (estimated). I tried looking for a while but was unable to find the kinetic friction of plastic wheels on cardboard.

Using Newton's second law, I was able to make this equation: F-Fk=ma, so F = ma+Fk. Fk is muK*Fn, so the final equation is: F=ma+muK*fn. Because there is no movement in the Y direction, fn would be the weight, and in this case 26.7n. there is no acceleration, so would ma equal zero?

Is there any way to find the kinetic friction between plastic and cardboard?

Thanks guys!
 
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  • #2
NutriGrainKiller said:
Working out some simple physics and I can't figure out how to convert velocity to Newtons for force..
Not surprising, since you can't "convert" velocities into forces in the first place.
What do you mean by this?
 
  • #3
arildno said:
Not surprising, since you can't "convert" velocities into forces in the first place.
What do you mean by this?

Well I think I answered that in my initial post, however there are more questions further down
 
  • #4
What exactly are you trying to figure out? Is the truck moving at constant velocity? Are the wheels rolling?
 
  • #5
It is really something you'd have to look up and you'd have to know the exact dimensions of what the tire is that is actually touching the ground.

Also, as arildno pointed out, velocity and force are two different things. It is like comparing temperature to density.
 
  • #6
NutriGrainKiller said:
Well I think I answered that in my initial post, however there are more questions further down
You can't convert a velocity into a force! Period.
 
  • #7
Doc Al said:
What exactly are you trying to figure out? Is the truck moving at constant velocity? Are the wheels rolling?

yes, slowly, about .067m/s

i figure i can find out the force with the coeffecient of kinetic friction between cardboard and plastic wheels, any way i can do this?
 
  • #8
Realize that if the car is moving at constant velocity, the net force is zero. Also, if the wheels are rolling (not slipping) then kinetic friction will not apply. And the static friction will be zero as well.
 
  • #9
From the power output of the motor that's driving the truck (and the velocity) you can find the driving force, using P = Fv
 

1. How do you convert velocity to Newtons?

The conversion from velocity to Newtons is not a direct one, as they are two different physical quantities. Velocity is a measure of an object's speed and direction, while Newtons are a unit of force. In order to convert velocity to Newtons, you would need to know the mass of the object and the rate at which its velocity is changing.

2. What is the formula for converting velocity to Newtons?

The formula for converting velocity to Newtons is F = m x a, where F is the force in Newtons, m is the mass of the object, and a is the acceleration. This formula is known as Newton's second law of motion and describes the relationship between force, mass, and acceleration.

3. Can you provide an example of converting velocity to Newtons?

Sure, let's say we have a car with a mass of 1000 kg, traveling at a velocity of 50 m/s. To convert this velocity to Newtons, we would multiply the mass by the acceleration. If the car's acceleration is 5 m/s^2, the force in Newtons would be 1000 kg x 5 m/s^2 = 5000 N.

4. Is there a specific unit for velocity to Newtons conversion?

No, there is no specific unit for converting velocity to Newtons. The unit for velocity is typically meters per second (m/s), while the unit for Newtons is kg*m/s^2. However, as long as the units for mass and acceleration are consistent, the result will be in Newtons.

5. What is the difference between velocity and Newtons?

Velocity and Newtons are two different physical quantities. Velocity is a measure of the speed and direction of an object, while Newtons are a unit of force. In other words, velocity describes how fast an object is moving, while Newtons describe the amount of force required to accelerate an object with a certain mass. They are related through Newton's second law of motion, which states that force equals mass times acceleration.

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