Calculating Mass and Force: A Pulley Problem

AI Thread Summary
The problem involves a 100 kg block that takes 5.40 seconds to reach the floor after being released from rest. The acceleration is calculated using the equation sf=si + (1/2)(a)(delta t), resulting in 0.0686 m/s². The force on the known mass is then determined using F=ma, yielding a force of 6.86 N. To find the mass of the block on the left, the tension in the system is considered, as it shares the same acceleration. The discussion concludes with the participant successfully understanding how to approach the problem.
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Homework Statement



The 100 kg blcok in the figure takes 5.40 s to reach the floor after being released from rest. What is the mass of the block on the left?
knight_Figure_08_33.jpg


Homework Equations


F=ma
sf=si + (1/2)(a)(delta t)


The Attempt at a Solution



I know to find acceleration you use
sf=si + (1/2)(a)(delta t)
0=1+(1/2)(a)(5.4)
a = 0.0686 m/s2

and then the F=ma to find the force on the block of known mass.
F=(100 kg)(0.0686)
F=6.86

but from this I am not sure how to determine the mass of the block on the left?
 
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Welcome to PF!

redlightgreen said:
a = 0.0686 m/s2

and then the F=ma to find the force on the block of known mass.
F=(100 kg)(0.0686)
F=6.86

but from this I am not sure how to determine the mass of the block on the left?

Hi redlightgreen! Welcome to PF! :smile:

Find the tension, T, and then use the fact that the block on the left has the same acceleration (in the opposite direction, of course). :wink:
 
oh okay! thank you so much.
i've got it now!
 

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