4. A worker exerts 140 N to push a 15 kg crate 20 meters across the floor. He then lifts the crate 2 meters up to a shelf.
a. How much work is done to push the crate across the floor?
b. What work was done to lift the crate up?
c. What was the total work done by the worker?

Engineers find a new metal that is stronger than steel but much lighter. this material is also significantly cheaper than what is currently used for most aircraft, available in large quantities, and easy to manufacture. the engineers are excited because this new material will lower the costs of buying and operating airplanes for companies. what is probably the best step for the engineers to make next?

Why is the use of carbon-14 limited

A4.0-cm tall light bulb is placed a distance of 32.0 cm from a concave mirror having a focal length of 16.0 cm. determine the image distance