Weight on a rocket accelerating upward

AI Thread Summary
A rocket accelerating upward at 20.0 m/s² affects the weight experienced by an astronaut standing on a scale. The astronaut's weight is calculated using F=ma, resulting in a force of 2100N. The discussion highlights the confusion in converting Newtons to kilograms, emphasizing that the scale reading should reflect the increased weight due to acceleration. The correct approach involves calculating the astronaut's effective weight during acceleration and understanding that it will be greater than their weight on Earth. Ultimately, the solution clarifies that the scale reading will indeed be higher than the astronaut's weight at rest.
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Homework Statement



"During the launch, a rocket is accelerated with 20.0m/s^2 upward. A 105.0kg astronaut is more concerned about his weight than about his safety and is standing on a scale. What is the scale reading in kg?"

Homework Equations



F=ma and also 4.45N=1lb

The Attempt at a Solution



So, first I solved F=ma with the information given to get 2100N, and since I don't think that N can convert to kg with an equation, I took from the front of the book that 1kg=2.20lbs where g=9.80m/s^2, so I thought that I could figure out what 1kg was with an acceleration of 20m/s^2, and I got that 4.5lbs would equal 1kg.

I then took my previous answer of 2100N and converted it to 471.9lbs and divided by 4.51lbs, hoping to get the correct kg with the acceleration given, but I got 104.6 which seems very wrong (first, because it's almost exactly the starting weight and second, because it should be higher, not lower than the starting weight). Thoughts?
 
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If his scale was calibrated on the Earth's surface, so that 1kg =2.2lbs, using just F=ma would yield you the correct answer.
On Earth he feels a weight of mg (105*9.8) of 1029N
When accelerating he feels a weight of ma (105*20) of 2100N
Find the ratio and multiply by his mass.
 
Oh, yeah I guess I was over-thinking it. Thanks!
 
No problem
 
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