In which of the following situations is work not being done?
A) Susanna lifts a letter to read it, using a force of 0.2 N.
B) A weightlifter holds a weight above his head using a force of 200 N.
C)A small bulldozer pushes a pile of dirt across the ground with a force
of 150 N
D)Johnny lifts a textbook from the floor to the top of his desk using a
force of 3 N.

An object weighs 40n in air, weighs 20n when submerged in water and 30n when submerged in a liquid of unknown density. what is the density of the liquid?

The ability to make things happen is also called a. heat b. force c. matter d. energy

Which of the following statements comparing electron microscopy and light microscopy is false? which of the following statements comparing electron microscopy and light microscopy is false? both the electron microscope and the light microscope use the same wavelengths for illumination. images produced by light microscopes can be in color, whereas electron microscope images are black and white unless they are artificially colored. the electron microscope has greater resolution than the light microscope. electron microscopes can allow examination of viruses and internal cell structures, whereas light microscopes are limited to objects that are 0.5 micrometers and larger. request answer