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What is work done by a person in moving a block of mass 2kg on a frictionless floor up to a distance of 5m?
Wiki User
∙ 9y ago
Scientifically, work is defined as force X distance. In this case, we know the distance (5 m), but we do not know the force. If we knew the original force applied we could calculate the work done. Or, if we knew the acceleration of the 2 kg mass when it was moved we could calculate the force (force = mass X acceleration; Newton's 2nd Law of Motion), then we could use that value to calculate the work done. However, with the information given, it is not possible to calculate the work done in this situation.
Perhaps, if we changed the scenario just a bit, we could calculate a different amount of work done. Let's say that by some means a person moved the 2 kg mass upwards, directly away from the center of the earth, to a height of 5 m. Since it is known that the acceleration due to gravity at most places on earth is 9.8 meters/sec/sec, we can calculate the force required to move the object as 19.6 kg.m/s/s (2 kg X 9.8 m/s/s). In the metric system, a kg.m/s/s is known as a Newton (N), so this would be 19.6 N. Using that force value, we can now calculate the work done as 98 N.m (19.6 N X 5 m). A N.m is known as a Joule (J, the metric unit for energy) so our answer would correctly read 98 J.
The question displays the natural, instinctive, popular, total fallacy that was logically disproven by Galileo about 500 years ago, and mathematically disproven by Newton about 400 years ago:
-- In order to keep an object moving, a force must be applied to it.
-- A moving object with no external forces applied to it will stop.
This concept makes complete common sense, matches all of our everyday experience, and is totally wrong.
The fact is: A moving object continues moving at constant speed in a straight line until an external force acts on it.
Work doesn't depend on the mass of the object or the distance it moves. The most massive object imaginable can move through an astronomical distance without any work being done on it at all.
The work done by the person is (force with which he pushes) multiplied by (distance through which he maintains that force).
If the object is already moving, the person doesn't have to touch it to make it move 5 m. He can just stand there and watch it. If it's not moving yet, then he can push as lightly as he wants, for as short a distance as he wants. The lightest imaginable force will cause the object to accelerate, with acceleration equal to (force) divided by (mass), and then, once it's moving, the force need not be maintained.
The force required is: Any force greater than zero, no matter how small.
The distance through which the force must be maintained is: Any distance greater than zero, no matter how small.
So the work done is: Any amount of work greater than zero, no matter how small. Regardless of the mass of the object, or how far you want to see it move. Moving a larger mass, or moving it a longer distance, does not
require more work, so long as the direction is not parallel to gravity and friction is negligible.
<<>> simple answer: no net work is needed to move a mass along a level frictionless floor because the force does not operate against gravity. Any horizontal force applied adds to the object's momentum and kinetic energy, then the object will move for ever until another force acts to stop it.
Apply a force F for time t, then the impulse Ft is equal to the change of momentum mV. So the speed is a constant one of Ft/m.
Work is initially done equalling the kinetic energy imparted to the mass as it is moved. None of this energy is dissipated by friction. Once it has gained momentum, that energy is stored until when it is stopped, at which point the kinetic energy is given up to whatever agent is causing the stop.
Wiki User
∙ 9y ago
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The coefficients of friction between a block of mass 1 kg and a surface are s0.64 and k0.42 Assume the only other force acting on the block is that due to gravity what is the magnitude of the fr?
In order for the frictional force to come into play the block must be moving or on the verge of moving. The Frictional force opposes the motion of the block or its "impending" motion. If the block is just sitting on a table with no horizontal forces trying to get it moving then the frictional force is zero.
If a block of concrete requires 2500 j to be moved 100m what is the weight of the block?
Work = force x distance;force = work/distance = 2500/100 = 25 Newtons weight which is about 2.5 kg mass
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What are you asking? This is the worst question I've ever seen. If your question is "is the block at a distance from the bottom of the table?". If so yes. If the table is frictionless, as well as the box, it doesn't matter if the box is at the edge. It will literally, assuming there wasn't gravity, go on forever.
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OK, it does. What of it? What precisely is your question?
A wooden block is released from rest at the top of a frictionless inclined plan and slides down to the bottomWhat convertions of energy are taking place as the block goes down the inclined plane?
Gravitational potential energy is converted into kinetic energy.
Will a propeller work in an ideal fluid?
no. it needs some viscous drag to throw the water and drag the ship forward... feel like a block just gliding in frictionless plane...
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the city block distance is the distance between two pixels. for example if we have two adjacent pixels their distance is 1 because they are adjacent. the this is used in edge detection applications
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An erratic block.
What is an example of a glacier moving boulder?
An erratic block.
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A moving large block of ice is known as a?
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A bullet weighing 10 g and moving at 300 meter per second strikes a 5 kg block of ice and drops dead if the ice block is on frictionless level the speed of the ice after the collision is?
Momentum before collision = momentum after collision =>0.01 x 300 = 5 x v => v = 0.01 x 300 / 5 = 0.6ms-1 or 60 cms-1 Therefore the speed of ice after collision is 0.6ms-1 or 60 cms-1
The coefficients of friction between a block of mass 1 kg and a surface are s0.64 and k0.42 Assume the only other force acting on the block is that due to gravity what is the magnitude of the fr?
In order for the frictional force to come into play the block must be moving or on the verge of moving. The Frictional force opposes the motion of the block or its "impending" motion. If the block is just sitting on a table with no horizontal forces trying to get it moving then the frictional force is zero.
