It takes energy to move any object horizontally and vertically. Lets say an object with weight 20N has moved a distance of 4m to the right and 3m upwards.
Work done = 20x3 = 60J
If an object ONLY moves 4m to the right, work done = 4x20 = 80J
So basically moving an object upwards and to the right requires LESS energy than simply moving an object to the right? This is a really conceptual thing and greatly confuses me :S Someone please explain this to me!
Work done = 20x3 = 60J
If an object ONLY moves 4m to the right, work done = 4x20 = 80J
So basically moving an object upwards and to the right requires LESS energy than simply moving an object to the right? This is a really conceptual thing and greatly confuses me :S Someone please explain this to me!
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Assuming there is no friction, it doesn't take ANY force to move an object horizontally.
If you do it very slowly (so the kinetic energy gained is negligible) no work is required because no energy is transferred to the object. If the object is already moving (e.g. on a frictionless surface) then it will continue to move horizontally with no force required (inertia - Newton's 1st Law). But if you apply a horizontal force, this gives it kinetic energy: the work done by the horizontal force = kinetic energy gained.
On the other, hand moving it upwards requires you to supply it with gravitational potential energy (+ extra energy if the kinetic energy gained is not negligible). The minimum energy needed to raise an object of weight W through a height is W x h.; this is the gain in gravitational potential energy.
The horizontal and vertical energy changes are completely separate. You certainly don't need to apply a horizontal force of 20N in your example. A horizontal force of 0.000000000001N will make it move horizontally but give it virtually no kinetic energy if there is no friction; the work done by this horizontal force would be negligible.
If you do it very slowly (so the kinetic energy gained is negligible) no work is required because no energy is transferred to the object. If the object is already moving (e.g. on a frictionless surface) then it will continue to move horizontally with no force required (inertia - Newton's 1st Law). But if you apply a horizontal force, this gives it kinetic energy: the work done by the horizontal force = kinetic energy gained.
On the other, hand moving it upwards requires you to supply it with gravitational potential energy (+ extra energy if the kinetic energy gained is not negligible). The minimum energy needed to raise an object of weight W through a height is W x h.; this is the gain in gravitational potential energy.
The horizontal and vertical energy changes are completely separate. You certainly don't need to apply a horizontal force of 20N in your example. A horizontal force of 0.000000000001N will make it move horizontally but give it virtually no kinetic energy if there is no friction; the work done by this horizontal force would be negligible.
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Work done
= force x displacement in the direction of the force
or
= component of force in the direction of displacement x displacement
= force x displacement x cos (angle between the force and displacement)
When the object is moved to the right, angle between the vertical force of weight and horizontal displacement is 90°
= force x displacement in the direction of the force
or
= component of force in the direction of displacement x displacement
= force x displacement x cos (angle between the force and displacement)
When the object is moved to the right, angle between the vertical force of weight and horizontal displacement is 90°
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