Question wording- incline question

  • Thread starter Thread starter caljuice
  • Start date Start date
  • Tags Tags
    Incline
Click For Summary
SUMMARY

The discussion centers on the analysis of a 4.5-kg mass moving up an incline at a 37-degree angle with an initial velocity of 14 m/s, which decreases to 5.2 m/s after an 8.0 m displacement. The equation used to find acceleration, vf² = vi² + 2ad, is correctly applied by subtracting the squares of the velocities and dividing by twice the displacement. The confusion arises from the interpretation of velocity directions; both the initial and final velocities are parallel to the incline, not vertical. Understanding this parallelism is crucial for accurately solving problems involving inclined planes.

PREREQUISITES
  • Understanding of kinematic equations, specifically vf² = vi² + 2ad
  • Knowledge of vector components in physics
  • Familiarity with inclined plane dynamics
  • Basic trigonometry, particularly sine and cosine functions
NEXT STEPS
  • Review kinematic equations in physics, focusing on their application to inclined planes
  • Study vector decomposition to clarify the relationship between different velocity components
  • Explore examples of motion on inclined planes to reinforce understanding of directionality
  • Learn about the effects of friction on inclined motion and how it alters acceleration
USEFUL FOR

Students studying physics, educators teaching mechanics, and anyone interested in understanding motion on inclined planes.

caljuice
Messages
70
Reaction score
0
The question was:

A 4.5-kg mass is given an initial velocity of 14 m/s up an incline that makes an angle of 37o with the horizontal. When its displacement is 8.0 m, its upward velocity has diminished to 5.2 m/s.

I'm confused with directions of the velocity. In the solution they used the equation

vf2=vi2+2*a*d

anyway to find 'a' they subtracted (142-5.22)/(2*8)

So doesn't this mean initial velocity and the upward velocity are parallel since they are being subtracted. I assumed the initial velocity would be parallel to the incline and the upward velocity completely vertical and thus i would have to 5.2/sin37.

When you read the question, what direction would you assume? Maybe it's right and I'm just mixing up the axis?
 
Physics news on Phys.org
Why would you assume the upward velocity was "completely vertical"? If the object were moving vertically, there would be no reason to mention the incline! The object is moving up the inclined plane. Yes, its velocity is always parallel to the incline.
 

Similar threads

Ambiguous question on momentum and how it works...
  • · Replies 13 ·
Replies
13
Views
1K
Question about Projectile Motion: Throwing a Flower Pot from a Balcony
  • · Replies 18 ·
Replies
18
Views
2K
Projectile Motion on an Incline
  • · Replies 6 ·
Replies
6
Views
3K
Inelastic collision with an inclined plane
  • · Replies 7 ·
Replies
7
Views
4K
Motion on a rough inclined plane
  • · Replies 5 ·
Replies
5
Views
2K
Kinematics on a frictionless incline plane
  • · Replies 3 ·
Replies
3
Views
2K
Cars Collide on a Hill, Conservation of Momentum
  • · Replies 7 ·
Replies
7
Views
3K
Conservation of Energy on a frictionless incline
  • · Replies 2 ·
Replies
2
Views
4K
Impulse on and the distance traveled by a cannonball
  • · Replies 2 ·
Replies
2
Views
2K
Block sliding up an inclined plane
  • · Replies 2 ·
Replies
2
Views
2K