Neither force is applied nor is work done
Answers
Explanation:
When is the work done zero if the force and displacement are not zero?
If the both the applied force and displacement are not zero the work done is zero if the two vectors are perpendicular to each other. Why is this statement true? What definition of work explains this?
Work is defined as the product of displacement and the applied force directed along the direction of displacement. Mathematically Work = F * d * cosθ where F is the applied force, d is the displacement and θ is the angle between force and displacement.
At any angle aside from 90 degrees and 270 degrees the work done is not zero if both F and d are nonzero. If θ is either 90 degrees or 270 degrees, the work done is equal to zero since the cosine of either 90 degrees or 270 degrees is equal to zero.
As an example of this is in this situation. A waiter carries a tray of food towards his customer using an upward force of 20 newtons. If his horizontal displacement is 5 meters how much work was done by him? Select from these choices: A) 100 joules, B) 0 joules, C) 25 joules, D) can’t be determined.
The correct answer is B) 0 joules.
Answer:
Think of work done as a measure of displacement in the direction of force times force. If the displacement is perpendicular to the direction of force or if it is zero then work done is equal to zero. So work done by the sun on earth is zero since centripetal force is perpendicular to the motion of the earth