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NotTim
Group Title
Determine the magnitude of the apparent weight of a 56 kg student standing in an elevator when the elevator is experiencing an acceleration of (a) 3.2 m/s^2 downward and (b) 3.2 m/s^2 upward.
 2 years ago
 2 years ago
NotTim Group Title
Determine the magnitude of the apparent weight of a 56 kg student standing in an elevator when the elevator is experiencing an acceleration of (a) 3.2 m/s^2 downward and (b) 3.2 m/s^2 upward.
 2 years ago
 2 years ago

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bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
W = m*a When it's going up, acceleration is: g+a, when it's going down acceleration is ga
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
a) total a = 9.83.2 = 13 W = 56*(13)N
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
You see, here's what I did for a and b.
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
b) total a = 9.8 + 3.2 = 6.6 W = 56*(6.6)N
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
a) f=ma =(56)(3.2+9.81) =728.56N
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
Why is the force negative in both cases?
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
because weight is pushing down.
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
Ok. Give me a second to redo this...
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
same thing, just change the signs
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
you found the normal force, which has the same magnitude, but opposite direction
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
And its alright if my signs are negative? Because the answers are A) 3.7*10^2N and b) 7.3*10^2N
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
ohh yea they asked for magnitude. If they just asked for weight, ur answers wld be negative
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
since weight has magnitude and direction. In this case it's going down, hence the negative.
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
k. ill work with this. if i need help, ill call out
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
Hey @bahrom7893 ?
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
the answer for A) was wrong. you probably explained this, but i forgot
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
We got 728.56N. The book says 3.7*10^2N
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
Wait in the answer, is the answer for a greater than the answer for b?
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
A) 3.7*10^2N and b) 7.3*10^2N Aren't those the answers?
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
oh yea.. obv. Hang on I know what we did wrong
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
for A), i did this: "56)(3.29.81)
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
well it makes sense.. i just always confuse the signs of g. g has to be positive in this case.
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
would that make my value of 3.2N positive too?
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
http://www.intuitor.com/student/elevatorrProblem.php
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
it's the sign of g, i always get confused with it..
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
am I to consider 3.2N a positive or negative force?
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
well is it pushing down or up?
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
It's pushing down
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
If it was ve, it would make sense mathematically, but not in terms of real world physics(for me)
 2 years ago

bahrom7893 Group TitleBest ResponseYou've already chosen the best response.1
then it's negative, but they're just asking for magnitude, or abs value of that force.
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.1
ok. give me a moment to readi guess
 2 years ago
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