Forces problemfind effective weight of mass (3 masses)

AI Thread Summary
The discussion revolves around calculating the effective weight of mass m3 in an elevator and determining the force needed to maintain constant velocity. Effective weight refers to the apparent weight experienced by an object, which changes based on the elevator's acceleration. Participants express confusion about the role of the applied force (f1) and the angle associated with it, questioning how to incorporate these into their calculations. There is a consensus that understanding the forces acting on each mass, including friction and gravitational forces, is crucial for solving the problem. Overall, the thread highlights the complexities of applying physics concepts to real-world scenarios like elevators.
needhelp12345
Messages
2
Reaction score
0

Homework Statement


http://i50.tinypic.com/r8gfba.png

^That is the image I got in class

m1=500kg
m2=1500kg
m3=10kg
f1=600n
angle near f1=25 degrees
coefficient of kinetic friction=.25

Find effective weight of m3 in side of elevator
Find force required to keep the elevator at constant velocity

Homework Equations


All I know is Ft=ft for both
I have a feeling f1 is either sin25(600) or cos25(600)..I don't know what 'effective weight' really means


The Attempt at a Solution



Would m1 just be 9.81(500) since it's going straight up and down..does Fn=Fg here?

For the second part, I know I probably have to set a to zero, but I can't do that when I don't know where to start
 
Physics news on Phys.org
Effective weight is the apparent weight of the object. Imagine you're standing in the elevator and it's moving up very fast. You are going feel heavier than if the elevator was not moving. If the elevator is moving down you will feel lighter.

Draw your fdb and then find acceleration.
 
I don't understand why the angle next to F1 is there, or why there is even an F1. What is it exactly? I can't attempt to find the overall force when I don't know what to do with that.

so, I think f1=253.6 N

For M2, is it (.25)(sin25)(1500)=ma

m1 is (9.81)(-500)=ma

and I combine? or do I add F1 to M2 first..or am I completely wrong?
 
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}...
View full post »

Thread 'Egg Drop Challenge! Need ideas for winning designs'

I was thinking using 2 purple mattress samples, and taping them together, I do want other ideas though, the main guidelines are; Must have a volume LESS than 1600 cubic centimeters, and CAN'T exceed 25 cm in ANY direction. Must be LESS than 1 kg. NO parachutes. NO glue or Tape can touch the egg. MUST be able to take egg out in less than 1 minute. Grade A large eggs will be used.
View full post »

Similar threads

Calculating Net Force of 3 Blocks in an Elevator
Replies
9
Views
2K
Olympiad dynamics problem with 3 masses and a pulley
Replies
17
Views
2K
Using Effective Mass to find the accelerations of 3 masses connected by pulleys
Replies
25
Views
3K
Solving for weight and mass in kg in an elevator
Replies
2
Views
3K
Calculate elevator acceleration using mass
Replies
9
Views
4K
Mechanics: Two masses on a pulley causing two cylinders to accelerate
Replies
16
Views
2K
Three masses in an elevator accelerating downwards
Replies
8
Views
3K
Magnitude of net Gravitational Force
Replies
1
Views
5K
I'm I on the right track? Tension question
Replies
21
Views
2K
Find mass of load that falls off truck
Replies
11
Views
7K

Hot Threads

Recent Insights

Back
Top