Forces - Elevator 2 part question

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    Elevator Forces
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To solve the elevator problem, start by applying the formulas for weight (w=mg) and Newton's second law (f=ma). When the elevator accelerates upwards, the scale reading increases due to the net force being the sum of the normal force and weight. Conversely, during downward acceleration, the scale reading decreases as the normal force is reduced. It's essential to create a free body diagram to visualize the forces acting on Larry in both scenarios. Summing the forces with the convention that upwards is positive and downwards is negative will clarify the calculations needed for each case.
Larrytsai
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Hi I just needed help with a question with 2 parts. I just need to know where to start and what formula is recommended for use.

For example:
Larry is standing on a scale in an elevator, the scale reads x. The elevator accelerates upwards at x m/s/s. The elevator weighs xx. How much does the scale read now?

Also same thing but acceleration is downwards.

Thanx for the help :D
 
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Do you have any formulae at all?
Do you understand the concept of what is happening when the elevator is moving?
 
the formulas that need to be used are w=mg, f=ma
and something about Sigma F
 
You need to sum your forces before and during the elevator movement. You know what weight is, mg. You know that before the movement there should only be 2 forces and they balance out. Now you need a free body diagram for the movement. You know that the elevator is moving upwards so sum your forces again and try from there.
 
when you say sum your forces, you mean like upwards is positive and downwards is negative so it would be Fn-W right?
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
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