What is the change in internal energy if 70 j of heat is added to a system and the system does 30 j of work on the surroundings?

a. 40 j
b. 100 j
c. -40 j
d. -100 j

Which of the following are considered noble gases? a. bromine b. neon c. argon d. chlorine

When a bicycle coasts uphill, it moves slower and slower as it climbs. why? a. its kinetic energy is transforming into heat energy. b. its potential energy is transforming into kinetic energy. c. its kinetic energy is transforming into potential energy and heat energy. d. its potential energy is transforming into kinetic energy and heat energy.

Suppose a wheel with a tire mounted on it is rotating at the constant rate of 2.15 times a second. a tack is stuck in the tire at a distance of 0.373 m from the rotation axis. noting that for every rotation the tack travels one circumference (a) find the tack's tangential speed. (b) what is the tacks radial acceleration?