How do you calculate friction

A ball is thrown straight up at an initial speed of 9.8m/s and, on returning to your hand, hits it moving downward at the same speed. If the whole trip took 2.0s, determine the ball's (a) average acceleration and (b) average velocity.

Which statement correctly relates the first and second laws of thermodynamics? Thermal-energy flow between objects is conserved and always flows from the warmer object to the cooler object.

f 720-nm and 620-nm light passes through two slits 0.68 mm apart, how far apart are the second-order fringes for these two wavelengths on a screen 1.0 m away

What does the force of gravity between two objects depend on?

An isolated conducting sphere has a 16 cm radius. One wire carries a current of 1.0000020 A into it. Another wire carries a current of 1.0000000 A out of it. How long would it take for the sphere to increase in potential by 1260 V?

you are not chilly when swimming in warm water. but when emerging from warm water on a warm summer day, you feel chilly if the wind is blowing. Explain

A Find the magnitude of the angular momentum of the second hand on a clock about an axis through the center of the clock face. The clock hand has a length of 15.0 cm and a mass of 6.00 g.

A geologist finds ripples preserved in ancient sedimentary rock that look just like ripples made by water in mud. He concludes that there was once water in that location that created the ripples. Why is this conclusion reasonable?

In science what is the requirement of doing work?

What Fitness Gram test is assessing your cardiovascular endurance?