you lift a chair that weighs 50 n to a height of 0.5cm and carry it 10 m across the room how much work do you do on the chair.
I just want to make sure is it 25J because you are only doing work if you are lifting it but walking with it isn't work because the direction of the objects motion isnt the same as the direction of force. Am I right?
Your argument is correct but do you really mean 0.5 cm? If so then work is 50 N * .005 meters.
Yes, you are correct. When you lift the chair to a height of 0.5 cm, you are doing work on the chair because you are exerting a force in the same direction as the displacement of the chair. However, when you carry it across the room for a distance of 10 m, you are not doing work on the chair because the force you exert is perpendicular to the displacement of the chair.
To calculate the work done in lifting the chair, you can use the formula:
Work = Force × Distance × cos(θ)
In this case, the force is the weight of the chair, which is 50 N, the distance is 0.5 cm (or 0.005 m), and θ is the angle between the force and the displacement (θ = 0° because they are in the same direction).
Plugging in the values:
Work = 50 N × 0.005 m × cos(0°)
= 50 N × 0.005 m × 1
= 0.25 J
So, the work done in lifting the chair is 0.25 Joules (J).
Since carrying the chair across the room is not considered work, the total work done on the chair would be 0.25 J.