Find frictional force given acceleration, grade, and mass

Click For Summary

Homework Help Overview

The discussion revolves around calculating the frictional force acting on a car moving down a slope with a specified grade while decelerating. The car's mass, acceleration, and slope percentage are provided, prompting questions about the relationship between these variables and the frictional force.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the application of Newton's second law (f=ma) and question whether the frictional force can be derived from the tangent of the slope angle. There are also considerations about the correct interpretation of the slope percentage and its relation to the angle.

Discussion Status

The conversation includes attempts to clarify the problem setup and the correct parameters to use. Some participants express confusion about the numbers and suggest drawing a free body diagram to visualize the forces involved. There is no explicit consensus on the approach to take, and multiple interpretations of the problem are being explored.

Contextual Notes

Participants note discrepancies in the problem's numerical values, indicating a mix-up between different problems. The slope is given as a percentage, which raises questions about how to convert this into an angle for calculations.

Butterfly30
Messages
28
Reaction score
0
a 1000 kg car is moving down a road with slope (grade) of 15% while slowing down at a rate of 3.7m/s^2 .What is the direction and magnitude of the frictional force?(define positive in the forward direction)


Using f=ma

I have the mass 1000 kg, the acceleration 3.7m/s^2, and slope 15%

Would my force be the tangent of the angle 15??
 
Physics news on Phys.org
Butterfly30 said:
a 1000 kg car is moving down a road with slope (grade) of 15% while slowing down at a rate of 3.7m/s^2 .What is the direction and magnitude of the frictional force?(define positive in the forward direction)

Using f=ma

I have the mass 1000 kg, the acceleration 3.7m/s^2, and slope 15%

Would my force be the tangent of the angle 15??
Without working the problem, I say no. For one thing the units are incorrect.
 
Sorry these were the numbers, I accidently mixed two probs together:/


a 1892kg car is moving down a road with slope (grade) of 12% while slowing down at a rate of 3.7m/s^2 .What is the direction and magnitude of the frictional force?(define positive in the forward direction)


Using f=ma

I have the mass 1000 kg, the acceleration 3.7m/s^2, and slope 15%

Would my force be the tangent of the angle 15??
 
So basically given this problem:


a 1892kg car is moving down a road with slope (grade) of 12% while slowing down at a rate of 3.7m/s^2 .What is the direction and magnitude of the frictional force?(define positive in the forward direction)

Would my force be the tangent of the angle 12??
With f=ma
 
Last edited:
Butterfly30 said:
Sorry these were the numbers, I accidentally mixed two probs together:/

a 1892kg car is moving down a road with slope (grade) of 12% while slowing down at a rate of 3.7m/s^2 .What is the direction and magnitude of the frictional force?(define positive in the forward direction)

Using f=ma

I have the mass 1000 kg, the acceleration 3.7m/s^2, and slope 15%

Would my force be the tangent of the angle [STRIKE]15[/STRIKE] 12??

The net force will be in a direction parallel to the ramp (down the ramp).

If the ramp makes an angle of θ with respect to the horizontal, then tan(θ) = 0.12 .

Draw a free body diagram.
 

Similar threads

Relation between Friction, Velocity, and Acceleration
  • · Replies 16 ·
Replies
16
Views
1K
A cylinder connected to a hanging mass
  • · Replies 21 ·
Replies
21
Views
2K
Coefficient of kinetic friction of a block sliding across the ceiling
  • · Replies 7 ·
Replies
7
Views
2K
Find the acceleration of the system (2 blocks sliding on a table)
  • · Replies 23 ·
Replies
23
Views
3K
Do the rail cars move on a 0.499% grade without brakes or external force?
  • · Replies 12 ·
Replies
12
Views
2K
How Does Friction and Acceleration Affect Tension in a Three-Block System?
  • · Replies 18 ·
Replies
18
Views
2K
Distribution of Energy when work is done on a system of 2 masses connected by a spring
  • · Replies 17 ·
Replies
17
Views
2K
Finding the work done by a block
  • · Replies 4 ·
Replies
4
Views
3K
Final Velocity of a car with a opposing decreasing drag force
  • · Replies 57 ·
2
Replies
57
Views
3K
Finding out the rotational speed of a mass
  • · Replies 59 ·
2
Replies
59
Views
5K