# Partice Kinetics Question - HELP

• Cam169677
In summary, the block is accelerating up the slope due to the kinetic coefficient of friction. However, the normal reaction force cannot be calculated due to the angle of the line on the pulley. Furthermore, the total force in the x-direction remains unknown.

## Homework Statement

As shown in the attachment.
At the instant shown the block is moving down the slope. What is the acceleration of the block up the slope if the kinetic coefficient of friction is 0.4?

## The Attempt at a Solution

I'm having problems with two things here, the calculation of the normal reaction on the block as i don't know what to do about the angle of the line on the pulley and its resultant force...
This leads to my second problem when summing the total force in the x-direction i still don't know what to do with the 47N force...

Generally i need help!

#### Attachments

• untitled1.JPG
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Welcome to PF!

Hi Cam169677! Welcome to PF!

(is 31º the angle between the upper rope and the slope, and is the lower rope suppposed to be parallel to the slope? )
Cam169677 said:
I'm having problems with two things here, the calculation of the normal reaction on the block as i don't know what to do about the angle of the line on the pulley and its resultant force...

There's no acceleration in the normal direction, so just use good ol' Newton's second law in that direction … ∑F = 0.
This leads to my second problem when summing the total force in the x-direction i still don't know what to do with the 47N force...

what's the x-direction?

the obvious direction to use is the direction of the slope …

then the component of the 47N in that direction is 47(cos31º)N

I'm also having trouble with this.

"is 31º the angle between the upper rope and the slope, and is the lower rope suppposed to be parallel to the slope?"

That's what i want to find out as well hmm

Welcome to PF!

Hi PcKSnipE! Welcome to PF!
PcKSnipE said:
"is 31º the angle between the upper rope and the slope, and is the lower rope suppposed to be parallel to the slope?"

That's what i want to find out as well hmm

I assume it is.

Alright i worked it out, the tricky bit has to do with the pulley.

The total force of the pullet in the X plane is T + TcosA
The force in the normal direction (which affects friction) is mgcosA - TsinA

Gl

i still don't get wat to do here guys i have a similar question but using the following example can u tell me step by step wat to do and a answer as well
Thanx much appreciated

welcome to pf!

hi jalwa! welcome to pf!

better start a new thread …

make sure to show us what you've tried, and where you're stuck, and then we'll know how to help!

## 1. What is particle kinetics?

Particle kinetics is the study of the motion and behavior of individual particles, such as atoms and molecules, in a system. It involves analyzing how these particles interact with each other and their surrounding environment.

## 2. How is particle kinetics different from thermodynamics?

While thermodynamics focuses on the overall properties of a system, particle kinetics focuses on the individual particles within the system. Thermodynamics deals with macroscopic variables such as temperature and pressure, while particle kinetics deals with microscopic variables such as velocity and energy.

## 3. What are some real-world applications of particle kinetics?

Particle kinetics is used in a variety of fields, including chemistry, physics, and engineering. It is used to study chemical reactions, diffusion, and the behavior of gases. It is also used in industries such as pharmaceuticals, where understanding the kinetics of drug molecules is crucial.

## 4. How is particle kinetics related to Brownian motion?

Brownian motion is the random movement of particles due to collisions with other particles. This phenomenon is an important part of particle kinetics, as it helps to explain how particles move and interact at a microscopic level.

## 5. How can particle kinetics be applied to improve technologies?

Particle kinetics can be used to better understand and optimize various technologies, such as chemical reactors, fuel cells, and semiconductor devices. By understanding the behavior of particles within these systems, scientists and engineers can make improvements to increase efficiency and effectiveness.