Friction resists

1- Movement
2- Motion
3- All the above
4- Sliding

How does the amount of energy required to hold each proton and neutron in the nucleus compare to the energy released when they are removed?

In a good thermo flask the main cause of heat loss is

22. the top of a cliff is located a distance h above the ground. at a distance h/2 there is a branch that juts out from the side of the cliff, and on this branch a bird's nest is located. two children throw stones at the nest with the same initial speed, one stone straight downward from the top of the cliff and the other stone straight upward from the ground. in the absence of air resistance, which stone hits the nest in the least amount of time?