- #31
anglum
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i have the ma+mg stuck in my head. and drawing it isn't helpin me in explaining to u where i am
Calculate the initial velocity of the elevator
- Thread starter anglum
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To calculate the initial velocity of a descending elevator that decelerates uniformly to rest over 4 meters, the tension in the cable and gravitational force are considered. The acceleration is determined to be 2.720 m/s², which is then used in the kinematic equation Vf² = Vi² + 2AD, with Vf as 0 and D as -4 m. The initial velocity is calculated to be approximately 4.67 m/s. The discussion also touches on related problems involving forces in elevators and the importance of correctly applying Newton's laws and understanding signs in calculations. Overall, the focus is on applying physics principles to solve motion problems effectively.
- #32
learningphysics
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It is always best to start your force problems by writing out the equations in the form:
\Sigma{F} = ma
and going from there... don't take shortcuts.
\Sigma{F} = ma
and going from there... don't take shortcuts.
- #33
anglum
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the force the earht exerts is
x = MA
x = 65*9.8
x=637N
x = MA
x = 65*9.8
x=637N
- #34
learningphysics
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anglum said:
don't get stuck with the ma + mg... always start from the basics...
\Sigma{F} = ma.
But anyway, for this problem, what is the force the Earth exerts on the student?
- #35
learningphysics
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anglum said:
yes. So what is the force the student exerts on the earth?
- #36
anglum
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the student exerts
X=5.98*10^24 * A
X=5.98*10^24 * A
- #37
anglum
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does X in this also equal 637N
- #38
learningphysics
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anglum said:
exactly.
- #39
anglum
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so then i solve it as 637/5.98*10^24 = A
A = 1.065217 *10^-22
A = 1.065217 *10^-22
- #40
anglum
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awesome... thank you soooooo much for all your help tonite... u are a very patient man and a very good teacher
- #41
learningphysics
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anglum said:
you're welcome. glad to help. keep at it! you're doing well!