A worker pushed a 25.0 kg block 6.50 m along a level floor at constant speed with a force directed 30.0° below the horizontal. If the coefficient of kinetic friction between block and floor was 0.410, what were (a) the work done by the worker's force and (b) the increase in thermal energy of the block-floor system?

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

When measuring volume, why is it important to use the correct tools and units to attain the greatest accuracy? use specific examples from the lab to support your answer. (5 points)

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