Elevator Definition and 567 Threads

Homework Statement In the figure, a 25 kg block is pulled by a 100 N force and slides across the floor of the elevator. The coefficient of friction is µ = 0.35. If the elevator is accelerating downward at 2.0 m/s2, what is the resulting acceleration of the block? See Figure 1 Homework...

Homework Statement A 5.0kg salmon is weighed by hanging it from a fish scale attached to the ceiling of an elevator. What is the apparent weight of the salmon if the elevator is (a) at rest, (b) moving upward at 2.5 m/s2, and (c) moving downward at 3.2 m/s2? Homework Equations Sum of F...

Homework Statement An elevator is moving upward at a constant speed of 2.50 {\rm{ m/s}}. A bolt in the elevator ceiling 3.00 {\rm m} above the elevator floor works loose and falls. (Part C) What is the speed of the bolt according to an observer standing on one of the floor landings of the...

Homework Statement A bolt comes loose from underneath an elevator that is moving upward at a constant speed of 6.0 m/s. The bolt reaches the bottom of the elevator shaft in 3.0 s. a.) How high above the bottom of the shaft was the elevator when the bolt came loose? b.) What is the...

Homework Statement http://img839.imageshack.us/img839/8904/bead.jpg Uploaded with ImageShack.us The picture speaks for itself. I'm asked to find the minimum velocty that this bead should be given so that it will reach point B. 2. The attempt at a solution I've solved this question using...

Hi, I am making a device with 8 INPUTs that will be connected to a long (5-25m) UTP cable running trough an elevator shaft (some interference, I imagine). Could you propose what kind of filters should I use on my inputs. The thing is, the HIGH level on these cables will be 12 to 19V but I need...

O.k., correct me if I'm wrong because I'm new to the concepts of relativity and other stuff, but I have a question. General Relativity says that, in the vacuum of space, there is no way to tell whether a downward force is being caused by gravity or constant acelleration, right? Well, I thought...

100 kg elevator acclerates up at rate avg a*. What's the avg force acting on the elevator if it covers a distance X over a period of 10s? a* denotes average accleration a. 2X + 1000 b. 100(a* + 1) c. 2a* + 1000 d. 2a*X I set up a free body diagram to show all the forces acting on the...

Homework Statement A person weighs a fish of mass m on a spring scale atached to the ceiling of an elevator. (a) Show that if the elevator accelerates either up or down, the spring scale gives a reading different from the weight of the fish. Homework Equations \SigmaFy=T-Fg=may...

Homework Statement A fully loaded freight elevator has a cab with a total mass of 1490 kg, which is required to travel upward 58 m in 2.1 minutes, starting and ending at rest. The elevator's counterweight has a mass of only 985 kg, so the elevator motor must help. What average power is...

Building a space elevator for the moon seems doable with existing materials (see the wikipedia page). So my question is why is no country or organization interested in building one?

I understand that surviving an elevator fall is unlikely, but physically speaking, what is one supposed to do to maximize one's chances of survival? Why?

Homework Statement I've gone out and measured my changing weight in an elevator using a bathroom scale, taking measurements each second, with the elevator ascending 4 storeys. I am wondering if it is possible to work out the acceleration of the elevator from these results, and if so how they...

Hello, first post. I hope that someone can help me with this. I will roughly summarize the problem, and what I've done thus far. Homework Statement A lady was in an elevator that free-fell 6 feet and abruptly came to a halt. We had to determine a reasonable best case and a reasonable worst...

Homework Statement An elevator system in a tall building consists of a 710 kg car and a 810 kg counterweight, joined by a cable that passes over a pulley of mass 280 kg. The pulley, called a sheave, is a solid cylinder of radius 0.700 m turning on a horizontal axle. The cable has comparatively...

Homework Statement A person weighing 0.6 kN rides in an elevator that has a downward acceleration of 3 m/s2. The acceleration of gravity is 9.8 m/s2 . What is the magnitude of the force of the elevator floor on the person? Answer in units of kN. Homework Equations F = ma The...

Homework Statement Henry gets into an elevator on the 50th floor of a building and it begins moving at t=0s. The figure shows his apparent weight over the next 12 seconds. Part A: Is the elevator's initial direction up or down? Explain how you can tell. Part B: What is Henry's mass...

Homework Statement Bill gets into an elevator on the 40th floor of a building and it begins moving at t = 0s. The figure shows his apparent weight over the next 12s. Is the Elevator moving up or down originally? What is his weight? How far does he travel over the first 12 seconds...

Homework Statement An elevator system (traction system) consists of a cab, a counterweight, and the motor-powered pulley. The cab and the counterweight is connected by a rope which is attached on the pulley. Consider the cab and the counterweight have equal mass = 1000 kg. The elevator is...

A 70kg person is in an elevator the elevator has an acceleration of 3m/s/s DOWNWARD. What force will the floor exert on the person. I am confused on the the equation. So far I think (mass)(acceleration)=(mass)(gravity)-(normal force). I know the mass is 70kg or 700N. I also know the...

Suppose a 70kg person is in an elevator. The acceleration of the elevator is -3m/s/s. What force would the floor exert on the person? Please show work...

Homework Statement A 563 N physics student stands on a bathroom scale in an 823 kg (including the student) elevator that is supported by a cable. At some time during her elevator ride, the scale reads 400 N. Find the acceleration of the elevator. Found this to be 2.84 m/s[SUP]2[SUP] in...

This is not an actual problem from my class. All our problems involved an elevator going upward (both accelerating and decelerating). But I am curious if an elevator cable would have the same FT if the elevator was decelerating downward at -3 m/s2 as it would accelerating upward at 3 m/s2 ? I am...

Homework Statement A person stands on a bathroom scale in a motionless elevator. When the elevator begins to move, the scale briefly reads only 0.76 of the person's regular weight. Calculate the magnitude of acceleration of the elevator. Homework Equations F=ma N=ma-mg The...

Homework Statement An elevator cable breaks when a 798 kg elevator is 28.9 m above a huge spring (k = 8.00 multiplied by 104 N/m) at the bottom of the shaft. (a) Calculate the work done by gravity on the elevator before it hits the spring. I got 226009 which is right (b) Calculate...

Homework Statement The effect of gravity is approximately 1/6 of what it is on Earth. If one were to build an elevator on the moon, (a) what would be the apparent weight of a 65kg astronaut when the elevator accelerates upward at 5 m/s2? (b) What is the acceleration of the elevator if the...

Homework Statement The motor of an elevator generates 12000 Watts of power when moving the elevator at constant speed of 2 m/s.what is the mass of elevator in kg ...?? There are 5 options for the answer. a) 500 Kg b) 400 Kg c) 300 Kg d) 240 Kg e) 200 Kg Homework...

[b] an elevator car weighing 50,000 N is 27m from the ground. the cable snaps and the elevator goes into free fall. Shock absorbers have been provided, the coil length is 1 m. Assume elevator is able to lock onto the shaft at the point of contact w/ the absorber so that it does not bounce...

1.A suitcase (mass m = 16 kg) is resting on the floor of an elevator. The part of the suitcase in contact with the floor measures 0.50 m by 0.14 m. The elevator is moving upward, the magnitude of its acceleration being 1.40 m/s2. What pressure (in excess of atmospheric pressure) is applied to...

Homework Statement A person stands on a bathroom scale in a motionless elevator. When the elevator begins to move, the scale briefly reads only 0.88 of the person's regular weight. Calculate the magnitude of the acceleration of the elevator. Homework Equations w=mg F=Ma The...

The tether generally proposed for a space elevator is usually made of carbon nanotubes. However, the lifters themselves are usually powered by lasers or some type of beamed energy. Two questions: 1. Carbon nanotubes can be very good conductors, why can't they be used to conduct electricity...

Homework Statement After watching a news story about a fire in a high rise apartment building, you and your friend decide to design an emergency escape device from the top of a building. To avoid engine failure, your friend suggests a gravitational powered elevator. The design has a large...

Homework Statement An elevator is accelerating upwards with acceleration a0. Two masses are hanging down from a pulley, connected to each other. I need to find the acceleration of m1, as viewed from within the elevator.Homework Equations The Attempt at a Solution If I look at each mass...

Homework Statement A 80.8 kg man inside a 40.0 kg dumb-waiter pulls down on the rope. At that moment the scale on which he is standing reads 200N. Determine the elevator's acceleration (basically the man is inside the elevator pulling a rope that goes around the pulley, which makes the...

I have been reading about the so called "SPACE ELEVATOR" in various articles in the news papers and magazines and reading that in a contest recently a company won a $900,000. prize as their creation climbed a mile long cable suspended from a helicopter in under 4 min. I understand that this...

Homework Statement A block, mass m, slides down a frictionless incline making an angle theta with an elevator floor. Find its acceleration relative to the incline when: a) elevator descends at a constant speed b) elevator ascends at a constant speed c) elevator descends with a constant...

Homework Statement •••23 In Figure 7-34, a 0.250 kg block of cheese lies on the floor of a 900 kg elevator cab that is being pulled upward by a cable through distance d1 = 2.40 m and then through distance d2 = 10.5 m. (a) Through d1, if the normal force on the block from the floor has...

Homework Statement An elevator with a small initial upward velocity being raised by a cable. The tension in the cable is constant. Find the magnitude of the tension in the cable. Be certain that the method you are using will be accurate to two significant figures. Acceleration=10 m/s^2...

Homework Statement Elevator cabs A and B are connected by a short cable and can be pulled upward or lowered by the cable above cab A. Cab A has mass 1700 kg; cab B has mass 1300 kg. A 12.0 kg box of catnip lies on the floor of cab A. The tension in the cable connecting the cabs is 1.91×10^4...

Homework Statement An empty elevator of mass 2.7x10 (3) kg is pulled upward by a cable at an acceleration of 1.2 m/s (2) a) What is the tension in the cable? b) What would be the tension in the cable if it was accelerating downward at 1.2 m/s (2)? c) What would be the tension in the...

I am designing a controller for an elevator. The elevator can be at one of two floors: Ground or First. There is one button that controls the elevator, and it has two values: Up or Down. Also, there are two lights in the elevator that indicate the current floor: Red for Ground, and Green for...

I am a fledgling undergrad with a potential mechanical engineering degree in my future. I just have a hypothetical question about the space elevator that yall may be able to help me with. I have not taken my physics courses yet so forgive my limited working knowledge of the material. If you...

Homework Statement Person with mass m = 80 kg stands on a scale during a ride in an elevator. How much weight shows on the scale, when the elevator is being moved evenly upwards (downwards) with velocity (speed) v = 1 m/s. How much weight shows on the scale when the elevator starts to move...

My answers for this problem aren't correct. Can anyone please help me spot my mistake. Thanks. Inside the elevator, masses m1 = 2.00kg and m2 = 4.00 kg are conncted by a cable A. Mass m1 is connected to the roof of the elevator by a cable B. The elevator has a downward acceleration of g/2...

Homework Statement An elevator, with people in it, has a mass of 1400 kgs. The motor is hooked up to the power grid that provides 220 volts of power. The elevator has to go up 30 meters at 4m/s. How many watts of potential (not sure if it's called that) are required to get the elevator...

A 88.0 kg person stands on a scale in an elevator. What is the apparent weight in each of the following situations? (a) when the elevator is accelerating upward with an acceleration of 1.40 m/s2 (b) when the elevator is moving upward at a constant speed (c) when the elevator is...

Say you have a space elevator 47000 km* long (well past the point where centripetal acceleration cancels out gravity) There is a vehicle traveling up the cable with a pretty high velocity, and instead of braking it just shoots off the top. (assume the counter weight allows this) At the...

If the elevator is accelerating downward, can you have a negative normal force being exerted on an elevator floor by a person? since the floor exerts an upward normal force on the person.

Homework Statement An elevator cable can stand a maximum tension of 19000N before breaking. The elevator has a mass of 520 kg, and a maximum acceleration of 2.16 m/s^2. Engineering safety standards require that the cable tension never exceed two-thirds of the breaking tension. How many 65-kg...

Homework Statement An elevator and its load have a combined mass of 2300 kg. Find the tension in the supporting cable when the elevator, originally moving downward at 12 m/s, is brought to rest with constant acceleration in a distance of 50 m. Homework Equations The Attempt at a...