Missing question: "how much work is done by the teacher?" (found on internet)
Solution:
The work done to move the desk across the floor is equal to

where F is the horizontal force applied to move the desk, and d is the distance covered by the desk. If we use F=20 N and d=5 m, we find the work done:
Answer:
600 Joules
Explanation:
Using the formula F*d*cosФ. Assuming the Ф is parallel to the motion. The work done is 600 Joules.
The oscillation of a body or system with its own natural frequency and under no external influence other than the impulse that initiated the motion. — called also free vibration. —opposed to forced oscillation.
Answer:Because kinetic energy is proportional to the velocity squared, increases in velocity will have an exponentially greater effect on translational kinetic energy. Doubling the mass of an object will only double its kinetic energy, but doubling the velocity of the object will quadruple its velocity.
Explanation: