What is the mass of block on the left?

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Homework Help Overview

The problem involves determining the mass of a block in a system where a 100kg block falls for 6.6 seconds after being released from rest. The context includes concepts from mechanics, specifically relating to forces and motion.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss using kinematic equations to find acceleration and relate it to the forces acting on the blocks. There are attempts to express the total mass in terms of the unknown smaller mass, and questions arise about how to solve for the total mass without knowing the smaller mass.

Discussion Status

Participants are actively exploring different approaches to relate the masses and acceleration. Some guidance has been offered regarding the use of equations, and there is a recognition of the need to express relationships between the masses involved.

Contextual Notes

There is an assumption that the system is in a state of equilibrium or uniform acceleration, and participants are working with the constraints of the problem without complete information about the smaller mass.

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Homework Statement



The 100kg block in the figure below takes 6.6s to reach the floor after being released from rest. What is the mass of block on the left?

http://i241.photobucket.com/albums/ff4/alg5045/p8-33.gif

Homework Equations



F=ma
kinematic equation

The Attempt at a Solution



I tried using accleeration = velocity/time, and I got .023 m/s^2. Then I used velocity = displacement/time, and I got .152 m/s. And then I got completely lost.
 
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You should be using
d = 0.5at^2 (assuming that initial v is 0)

so get a, and then
you know the system is moving with a

therefore weight of larger mass - wieght of smaller mass = (total mass)*a
 
Ok, for the acceleration I got .046m/s^2. How do I figure out what the total mass is since I don't know the smaller mass?
 
aligass2004 said:
Ok, for the acceleration I got .046m/s^2. How do I figure out what the total mass is since I don't know the smaller mass?

you want to solve for the smaller mass... write the total mass in terms of the smaller mass...
 
So larger mass-smaller mass = (larger mass + smaller mass)a
 
aligass2004 said:
So larger mass-smaller mass = (larger mass + smaller mass)a

(larger mass)*g - (smaller mass)*g = (larger mass + smaller mass)a
 
Got it after three tries at manipulating the equation. 99.067kg.
 

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