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W = m*a
When it's going up, acceleration is: g+a, when it's going down acceleration is g-a

a) total a = -9.8-3.2 = -13
W = 56*(-13)N

You see, here's what I did for a and b.

b) total a = -9.8 + 3.2 = -6.6
W = 56*(-6.6)N

a) f=ma
=(56)(3.2+9.81)
=728.56N

Why is the force negative in both cases?

because weight is pushing down.

Ok. Give me a second to redo this...

same thing, just change the signs

you found the normal force, which has the same magnitude, but opposite direction

And its alright if my signs are negative? Because the answers are A) 3.7*10^2N and b) 7.3*10^2N

ohh yea they asked for magnitude. If they just asked for weight, ur answers wld be negative

since weight has magnitude and direction. In this case it's going down, hence the negative.

k. ill work with this. if i need help, ill call out

Hey @bahrom7893 ?

hey

the answer for A) was wrong. you probably explained this, but i forgot

We got -728.56N. The book says 3.7*10^2N

Wait in the answer, is the answer for a greater than the answer for b?

No.

A) 3.7*10^2N and b) 7.3*10^2N
Aren't those the answers?

yup

oh yea.. obv. Hang on I know what we did wrong

for A), i did this: "56)(-3.2-9.81)

well it makes sense.. i just always confuse the signs of g. g has to be positive in this case.

would that make my value of 3.2N positive too?

http://www.intuitor.com/student/elevatorrProblem.php

it's the sign of g, i always get confused with it..

am I to consider 3.2N a positive or negative force?

well is it pushing down or up?

It's pushing down

If it was -ve, it would make sense mathematically, but not in terms of real world physics(for me)

then it's negative, but they're just asking for magnitude, or abs value of that force.

ok. give me a moment to readi guess