Why is friction between moving parts of machines undesirable?

A number has a atomic number of 9 and an atomic mass of 19 amu. how many protons and how many neutrons are present in the atom

The amount of work done depends on what two things

8. A book is pushed a distance of 0.78 m by a force that gives the book an acceleration of 1.54 m/s². If 1.56 J of work is done on the book, what is the book's mass?

An object has a total kinetic energy of 2,400,000 J. If it's mass is 0.004 kg, then what is it's velocity.

Why are concepts in physics described in formulas?

Which statement about how light travels is true? A Light waves need a medium to travel, and they travel at the same speed even if the light source is moving.

Explain why the car reaches a top speed even though the thrust Force remains constant at 3500N

4. A helicopter is flying at a height of 1.5km. If it has 50MJ of G. P. E., what is the mass of the helicopter?

Unless otherwise posted, what is the speed limit in a school zone? florida

If you put in 10 J of work to push 1 c of charge against and electric field what will be its voltage with respect to its starting position? when released, what will be it's kinetic energy if it flies past it's starting position?