# Calculating Friction Force of a 4000 kg Truck on a 15° Slope

• kdb004
In summary, the problem involves finding the friction force of a 4000 kg truck parked on a 15 degree slope. The conversation suggests that the student is seeking help because their professor does not adequately teach the material. The solution involves drawing a free body diagram of the truck on the incline.
kdb004

## Homework Statement

A 4000 kg truck is parked on a 15 degree slope. what is its friction force?

please show work, i'd like to understand how to do this problem

*** my college professor doesn't really teach in class, well let me take that back. he teaches some things but leaves us hangin out to dry for pretty much everything else so pretty much everyone resorts to using online help like this***

Well you should start by drawing a FBD of the truck on an incline and go on from there.

ya, I am not going to lie. i don't even know how to do that.

iRaid said:
Well you should start by drawing a FBD of the truck on an incline and go on from there.

ya i don't really know how to do that

I understand the frustration of not receiving proper instruction from a professor. I am happy to help you with this problem and explain the steps involved in calculating the friction force on the truck.

First, we need to understand the concept of friction force. Friction force is the force that opposes motion between two surfaces in contact with each other. In this case, the truck is parked on a slope, so the force of gravity is pulling it downhill. The friction force will act in the opposite direction, preventing the truck from sliding down the slope.

To calculate the friction force, we will use the formula F = μN, where F is the friction force, μ is the coefficient of friction, and N is the normal force. The coefficient of friction is a constant that depends on the nature of the surfaces in contact. In this case, we will assume a coefficient of friction of 0.6, which is a reasonable estimate for a truck on a road surface.

The normal force is the force exerted by the surface on the truck, perpendicular to the surface. In this case, the normal force will be equal to the weight of the truck, which can be calculated using the formula W = mg, where m is the mass of the truck and g is the acceleration due to gravity (9.8 m/s^2).

Now, let's plug in the values into the formula: F = μN = μmg = (0.6)(4000 kg)(9.8 m/s^2) = 23520 N.

So the friction force acting on the truck is 23520 N. This means that the truck would need a force greater than 23520 N in order to start moving down the slope. I hope this explanation helps you understand the process of calculating friction force. Let me know if you have any further questions.

## 1. How do you calculate the friction force of a 4000 kg truck on a 15° slope?

To calculate the friction force, you will need to know the weight of the truck (4000 kg) and the inclination of the slope (15°). The formula for calculating friction force is: Friction Force = Normal Force * Coefficient of Friction. Normal force is equal to the weight of the truck multiplied by the cosine of the angle of the slope. The coefficient of friction can vary depending on the surface the truck is on, but it is typically between 0 and 1. Once you have these values, you can plug them into the formula to calculate the friction force.

## 2. What is the normal force in the calculation of friction force?

The normal force is the perpendicular force exerted by a surface on an object in contact with it. In this case, it is the force exerted by the slope on the truck. It is equal to the weight of the truck multiplied by the cosine of the angle of the slope.

## 3. How does the angle of the slope affect the friction force?

The angle of the slope directly affects the normal force, which in turn affects the friction force. As the angle of the slope increases, the normal force decreases, resulting in a decrease in friction force. This is because the weight of the truck is distributed more evenly across the slope as the angle increases, reducing the force pushing down on the surface.

## 4. What is the coefficient of friction and how does it impact the friction force?

The coefficient of friction is a measure of the amount of friction between two surfaces. It is a unitless value typically between 0 and 1, with lower values indicating less friction and higher values indicating more friction. The coefficient of friction impacts the friction force because it is multiplied by the normal force in the calculation. A higher coefficient of friction will result in a higher friction force, and vice versa.

## 5. Can the friction force be greater than the weight of the truck?

No, the friction force cannot be greater than the weight of the truck. The maximum amount of friction force that can be exerted is equal to the normal force, which is equal to the weight of the truck in this case. Friction force can only act in the opposite direction of motion, so it cannot exceed the weight of the truck pushing down on the slope.

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