Need help with Incline Plane Problem

In summary, in this conversation, the problem of a 10 kg block of ice sliding down a frictionless ramp was discussed. The acceleration of the block was found to be 1.7 m/s² and the coefficient of kinetic friction was calculated to be 0.10. The process of finding the friction force and solving for time using a kinematic equation was also discussed.
  • #1
jord12321
13
0
Need help with Incline Plane Problem!

Homework Statement


A 10 kg block of ice slides down a ramp 20 m long, inclined at 10 degrees to the horizontal.
a) If the ramp is frictionless, what is the acceleration of the block of ice? (I was able to do this question the answer is 1.7 m/s²)

b) If the coefficient of kinetic friction is .10, how long will it take the block to slide down the ramp, if it starts from rest?

So right now I know I have...
m= 10 kg
d= 20 m
sin10
cos10
v1= 0 m/s
a= 1.7 m/s²


Homework Equations


I'm really not sure what to do.


The Attempt at a Solution


I'm not sure what to do, I need to know where to start!
 
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  • #2


jord12321 said:

Homework Statement


A 10 kg block of ice slides down a ramp 20 m long, inclined at 10 degrees to the horizontal.
a) If the ramp is frictionless, what is the acceleration of the block of ice? (I was able to do this question the answer is 1.7 m/s²)

b) If the coefficient of kinetic friction is .10, how long will it take the block to slide down the ramp, if it starts from rest?

So right now I know I have...
m= 10 kg
d= 20 m
sin10
cos10
v1= 0 m/s
a= 1.7 m/s²


Homework Equations


I'm really not sure what to do.


The Attempt at a Solution


I'm not sure what to do, I need to know where to start!

To start with, you should probably draw a FBD of the block on the ramp. :smile:
 
  • #3


Ok i did that, I just don't know what to solve for first.
 
  • #4


Alright, so you drew your FBD.

You have a Weight force going down.
A normal force going perpendicular to the ramp's surface.
A friction force going the opposite direction of motion.

Correct?

Now... 2 questions for you.

[itex]\Sigma[/itex]F[itex]_{y}[/itex]= ?
[itex]\Sigma[/itex]F[itex]_{x}[/itex]= ?
 
  • #5


correct,
fx = sin10mg = sin10 x 10 x 9.8 = 17
fy = cos10mg = cos10 x 10 x 9.8 = 96
 
  • #6


Where is your friction force? I can't tell if you have one or not.
 
  • #7


What do you mean? Didn't i just solve for parallel and perpendicular force?
 
  • #8


I might be missing something myself; running on very little sleep here. Sorry.
 
  • #9


I don't have the force of friction yet.
 
  • #10


I was able to get friction because fn = f perpendicular. So i did .10 x 96 and got friction to equal -9.6
 
  • #11


Ok, so after looking at this myself...

I get.

[itex]\Sigma[/itex]F[itex]_{x}[/itex]=mg*sin[itex]\Theta[/itex] - [itex]\mu[/itex]mg*cos[itex]\Theta[/itex]

I'm still working on Fy.
 
  • #12


Ok, thanks for your help!
 
  • #13


jord12321 said:
I was able to get friction because fn = f perpendicular. So i did .10 x 96 and got friction to equal -9.6

Friction = [itex]\mu[/itex]mg*cos[itex]\Theta[/itex]

The reasoning:

N = -mg*cos[itex]\Theta[/itex]

So, friction = -.10*98*cos(10) = -9.65 N

Correct?You're welcome, but I don't know how much help I was. :/ Fy always gets me in these problems.
 
  • #14


Aggression200 said:
Friction = [itex]\mu[/itex]mg*cos[itex]\Theta[/itex]

The reasoning:

N = -mg*cos[itex]\Theta[/itex]

So, friction = -.10*98*cos(10) = -9.65 N

Correct?


You're welcome, but I don't know how much help I was. :/ Fy always gets me in these problems.

I got the same answer as you.
 
  • #15


jord12321 said:
I got the same answer as you.
Right. And you can find acceleration from there, correct?
 
  • #16


Correct, but I'm suppose to find time.
 
  • #17


Then you use the acceleration and plug it into a kinematic equation.

You have delta x, acceleration, and an initial velocity.

So, you have to find your time using...

[itex]\Delta[/itex]x = V[itex]_{i}[/itex]t + 1/2(a)(t[itex]^{2}[/itex])

Please correct me if I'm wrong.
 
  • #18


You are right! Thank you so much for helping!
 
  • #19


You're very welcome!
 

1. What is an incline plane problem?

An incline plane problem is a physics problem that involves an object moving on an inclined surface, where gravity is acting on the object. The goal is usually to find the acceleration, velocity, or force acting on the object.

2. How do I solve an incline plane problem?

To solve an incline plane problem, you will need to use the principles of physics, such as Newton's laws of motion and the equation for calculating force (F=ma). You will also need to use trigonometry to calculate the components of force and acceleration in the direction of the incline.

3. What information do I need to solve an incline plane problem?

You will need to know the mass of the object, the angle of the incline, and the coefficient of friction between the object and the incline. You may also need to know the initial velocity or acceleration of the object.

4. Can I use a calculator to solve an incline plane problem?

Yes, you can use a calculator to solve an incline plane problem. You will need to use trigonometric functions, such as sine, cosine, and tangent, to calculate the components of force and acceleration. Some calculators even have built-in functions for solving incline plane problems.

5. Are there any tips for solving incline plane problems?

Some tips for solving incline plane problems include drawing a free-body diagram to visualize the forces acting on the object, breaking forces into components parallel and perpendicular to the incline, and using the correct units for calculations. It is also helpful to practice solving similar problems to become more familiar with the process.

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