How could you increase the sliding friction between the sled and track? How could you decrease it?

What happens to matter when we add or take away heat energy?

If the faster stone takes 12.0 s to return to the ground, how long will it take the slower stone to return?

Why don't animal cells need chloroplasts? A) Animals do not make their own food. B) Animal cells make their own chlorophyll. C) Animal cells collect sunlight another way. D) Animals use photosynthesis to make their own food.

A girl rides her bike at 15 m/s for 20 s. How far does she travel in that time? 300m How fast would the girl in the previous problem have been traveling if she had covered the same distance in 11 seconds?

Hot air enters a rectangular duct (20cm wide, 25cm high, and 5m long) at 100 kPa and 60 degrees C at an average velocity of 5 m/s. While air flows the duct, it gets cool down (loses energy) so that air leave the duct at 54 degrees C.

A piano tuner hears three beats per second when a tuning fork and a note are sounded together and six beats per second after the string is tightened. What should the tuner do next, tighten or loosen the string? Explain.

How much work is done? A Net Force of 9.0 N acts through a distance of 3.0 m in a time of 3.0 s. The answers are 3.0 J, 9.0 J, 27 J, 81 J.

Two capacitors are identical except that they have different insulators in the gap between the conductors. Capacitor A has an air filled gap while capacitor B uses a material with dielectric constant 3 to keep the conductors apart.

The intensity of the sun's radiation incident upon the earth is about i=1.4kw/m2. suppose this is the value for the intensity of sunlight incident upon the satellite's solar panels. what is the total solar power p absorbed by the panels?

Which possible discovery would be attributed to an inorganic molecule? a protein that contains more energy than lipids a fireproofing spray used in firefighting a new energy-efficient fuel source a synthetic polymer that resists degrading