Which of these is the best definition of a fuel cell?

A 20-N falling object encounters 4 N of air resistance. The magnitude of the net force on the object is?

All of the bones in your body, with the exception of the hyoid joint in the neck, form a joint with another bone. True or False?

A 15 g bullet is fired horizontally into a block of wood with a mass of 2.5 kg and embedded in the block. initially the block of wood hangs vertically and the impact cause the block to swing so that it its center of mass rises 15 cm.

Explain reflection and refraction

Consider a stone at rest on the ground. There are two interactions that involve the stone. One is between the stone and the Earth; Earth pulls down on the stone and the stone pulls up on the Earth. What is the other interaction? 1. All are wrong. 2.

How would life on earth be different if earth's axis were not tilted with respect to its orbit? A. There would be no seasons. B. There would be no day and night. C. All places would have the same climate. D. The seasons would be much shorter.

What will a spring scale read for the weight of a 75.0-kg woman in an elevator that moves upward with constant speed of 5.8 m/s?

What's the definition of: • cellular respiration • photosynthesis

What are the steps that are important to take for your safety during an earthquake? a. stay away from walls and windows c. stay away from electrical and gas lines b. get under a desk or table d. all of the above

You have an open air column of length 1.40 m in air at 24.2 °C. What is the frequency of the third harmonic?