How to find mass in an Atwood machine

AI Thread Summary
In an Atwood machine scenario, a 5kg weight causes a pumpkin to accelerate downwards at 4.65 m/s². To find the mass of the pumpkin, the tension in the rope and gravitational forces must be analyzed. The initial calculations suggest that the pumpkin's mass is greater than 5kg, leading to confusion about the correct formulas to use. Participants debate the appropriate equations for tension and mass, indicating that the formulas presented may be incorrect. Clarification on the forces acting on both the pumpkin and the weight is essential for accurate mass determination.
iyanna
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Homework Statement



A pumpkin and a weight are attached to a frictionless pulley. As the 5kg weight is released, the pumpkin accelerates down at 4.65 m/s^2 to the ground. What is the mass of the pumpkin? [/B]

Homework Equations



How do I find the mass?

The Attempt at a Solution



T=m1g
ma=m2g-T
m=m2g-T/a
m=m2g-49/4.65
m=10.53-m2g
m-10.53=m2g
10.53+5=15.53
m2=1.57kg
 
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It says the pumpkin accelerates downwards. Does that make it more or less than 5kg?
 
haruspex said:
It says the pumpkin accelerates downwards. Does that make it more or less than 5kg?
More
 
You don't make it clear, but I assume you are using m ( or m1) for the mass of the weight and m2 for the pumpkin.
If T is the tension in the rope, what are the forces acting on the pumpkin? What "F=ma" equation does that give you? Same questions for the weight.
 
I think your formula is off.

Shouldn't it be m2 = (ma + T) / g ?
 
Kamisama said:
I think your formula is off.

Shouldn't it be m2 = (ma + T) / g ?
How is that different from
iyanna said:
ma=m2g-T
?
 

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