Newtons Law / Kinematic problem?

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Homework Help Overview

The problem involves a block of ice sliding down a frictionless ramp, and participants are tasked with determining the angle of the ramp based on kinematic principles. The subject area includes kinematics and potentially energy conservation, though the latter has not yet been covered in the original poster's class.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to use kinematic equations to find acceleration and subsequently the angle of the ramp. Some participants question the arithmetic involved and suggest that a conservation of energy approach might be more suitable, despite the original poster's current focus on kinematics.

Discussion Status

The discussion is ongoing, with participants providing feedback on the original poster's calculations and suggesting alternative perspectives. There is recognition of a potential arithmetic error in the original poster's work, but no consensus has been reached on the correct approach or solution.

Contextual Notes

The original poster notes that their class has not yet covered energy concepts, which may limit their ability to explore that approach. Additionally, there is mention of a discrepancy in numerical values due to a misunderstanding in the problem setup.

physstudent1
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Hello, the question I'm having trouble with is:

"A 8.00kg block of ice, released from rest at the top of a 1.5 m long frictionless ramp, slides downhill, reaching a speed of 2.5 m/s at the bottom.
What is the angle between the ramp and the horizontal?"

My first attempt to solve this problem was that I would use kinematics to get the acceleration. And then use the acceleration and Newton's laws to find the angle. By using kinematics I got the equation 2.5^2 = 0 + 2(a)(1.5)
I then got a to be 1.64. Using that I set the equation 8gsin(theta) = 1.64(8). Eventually getting theta to equal 9.6 degrees. But when I compared my answer to the a fellow classmate He got 12.275, but I can't really follow his work and there's no answer in the back of the book, so can anyone help?
 
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Since there is no friction, it may be easier to consider this problem as a conservation of energy problem.
 
We have not gotten to energy yet in my class :(. This is the third chapter all we have done is kinematics, projectile motion, and now this.
 
I've just looked through your work and it appears it's just your arithmetic that's letting you down. Your kinematic equation is correct, but your value for acceleration is not; try solving for acceleration again.
 
Ah jeez I'm so dumb thanks a lot! I just have sloppy hand writting so I turned the 1.5 into a 1.9 which gave me the wrong answer thanks a lot.
 

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