Distance Question: 11kg Block Sliding Down 24° Frictionless Slope

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Homework Help Overview

The problem involves a block of mass 11 kg sliding down a frictionless slope inclined at an angle of 24°. The block starts from rest and takes 1.85 seconds to slide down the slope. Participants are tasked with determining the total distance the block slides.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the calculation of acceleration using forces and question the values used in the calculations. There is a focus on the correct application of trigonometric functions related to the slope's angle.

Discussion Status

The discussion is ongoing, with participants identifying errors in the calculations and suggesting corrections. There is no explicit consensus yet, but guidance has been offered regarding the correct use of trigonometric functions in determining acceleration.

Contextual Notes

Some participants express confusion over the calculations of force and acceleration, noting that the values derived seem inconsistent with the expected physics principles. The discussion reflects a need to clarify the application of forces on an inclined plane.

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Homework Statement


A 11 kg block slides down a frictionless slope
which is at angle θ = 24◦. Starting from rest,
the time to slide down is t = 1.85 s.
The acceleration of gravity is 9.8 m/s2 .
(look at image)
What total distance s did the block slide?
Answer in units of m.

Homework Equations


F=ma
F=mg
tan(theta) = Fy/Fx

The Attempt at a Solution


I calculated the acceleration, a = F/m = 22.01116038m/s^2.
I used the time 1.85sec and the acceleration to find the velocity, v = 40.72064671m/s.
I don't know how to proceed from this point?
 

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allora_97 said:

Homework Statement


A 11 kg block slides down a frictionless slope
which is at angle θ = 24◦. Starting from rest,
the time to slide down is t = 1.85 s.
The acceleration of gravity is 9.8 m/s2 .
(look at image)
What total distance s did the block slide?
Answer in units of m.

Homework Equations


F=ma
F=mg
tan(theta) = Fy/Fx

The Attempt at a Solution


I calculated the acceleration, a = F/m = 22.01116038m/s^2.
I used the time 1.85sec and the acceleration to find the velocity, v = 40.72064671m/s.
I don't know how to proceed from this point?

What numbers did you use for F/m?

22 is way too high. It has to be under 9.8
 
I found Fn = mg = 107.8
I used Force = Fn/tan24 = 242.1227642N
then i found a = F/m = 242.1227642N/ 11kg = 22.01116038 m/s^2
 
I think you should have multiplied by tan(theta), not divided by it.
 
thanks
 
allora_97 said:
I found Fn = mg = 107.8
I used Force = Fn/tan24 = 242.1227642N
then i found a = F/m = 242.1227642N/ 11kg = 22.01116038 m/s^2

There's your mistake.

Multiply the force by sin(theta) then use that force in F/m to get your acceleration.
 

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