Fictional force problem given a slope(grade)?

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In summary: The slope is causing the car to accelerate, so the force acting on the car is a function of both the mass of the car and the slope of the slope. The magnitude of the force is determined by the mass and the slope. The direction is determined by the trigonometric function.
  • #1
fictional force problem...given a slope(grade)?

A 1000kg car is moving down a road with a slope(grade) of 15% at a constant speed of 15m/s. What is the direction and magnitude of the frictional force?

So...

V= 15m/s
a= 0 (constant)

The slope really throws me off..I don't know where to start! And the percent... What am I supposed to do with that??
 
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  • #2


Look up what grade means. If there were no friction, the car would be accelerating. But it isn't. Therefore what can you say the friction force must equal?
 
  • #3


Zero? The frictional force would be zero. So, then the grade (the incline) was given just to make us think and try to picture it, I guess.

Ok, how about if we're given the grade and told that the the car was speeding up at 3m/s^2

I know the mass (1000kg) and I think theta would be the percentage of 15? Would the velocity be the force N or friction f? and where would I plug in my acceleration?

I think f=ma ; Ncos(theta) + fcos(theta)-mg

I hope I'm on the right track...the prof. has only touched on the subject and he hasnt assigned a textbook..so really I'm trying to google what I can but its more complicated than I can do on my own. Any help would be appreciated :)
 
  • #4


Friction is not zero. If it were zero, the car would be accelerating. It is not. It is moving at constant speed.

For the car to move DOWN the slope at a CONSTANT speed, what forces must be equal and opposite.
 
  • #5


Would it be equal to the mass?
 
  • #6


Mass is not force. Mass times acceleration is force. The force that propels the car down the slope is a function of mass, gravity (acceleration), and a trigonometric function of the angle of the slope.

You should draw a free body diagram of the vehicle on the slope and determine what the acting forces are. Obviously, gravity and the downhill directions do not coincide. Therefore there is a trigonometric relationship between them.
 

What is a fictional force problem given a slope?

A fictional force problem given a slope is a physics problem that involves calculating the force required to move an object up or down a slope, taking into account the effects of fictional forces such as friction and gravity.

How do I solve a fictional force problem given a slope?

To solve a fictional force problem given a slope, you will need to use the equations of motion and Newton's laws of motion to calculate the net force acting on the object. You will also need to take into account the angle of the slope and the coefficients of friction for the surfaces involved.

What are some common examples of fictional force problems given a slope?

Some common examples of fictional force problems given a slope include pushing a box up a ramp, skiing down a hill, or pulling a sled across the snow. These problems can also involve more complex scenarios, such as an object sliding down a curved surface or a car driving around a banked turn.

What is the role of the slope in a fictional force problem?

The slope plays a crucial role in a fictional force problem as it determines the angle at which the object is moving and the amount of gravitational force acting on it. The slope also affects the magnitude and direction of other fictional forces, such as friction, which can either aid or hinder the movement of the object.

How can I check my answer for a fictional force problem given a slope?

To check your answer for a fictional force problem given a slope, you can use the equations of motion to calculate the acceleration, velocity, and position of the object at different points along the slope. You can then compare these values to your initial calculations to ensure they are consistent and accurate.

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