Ahand lifts a block vertically upward at constant velocity. the work done by gravity on the block if the system consists of the block only. and why?
a) is zero,
b) is zero/is zero,
c) is negative/is zero,
d) is positive/is negative,
e) is negative/is positive,
f) is positive

A30 kg weight lies on top of a massless piston of area a = 0.01 m2 the exterior air is at a (constant) p =1 atm and t = 27 c. the interior gas is 0.4 moles of (ideal) n2 and it has initial temperature 27.00 degrees c. 1. what is the initial pressure in the interior? a. 29.4 kpa b. 130.7 kpa c. 101.3 kpa the next three questions concern what happens when an amount of heat q is slowly added to the interior, raising the piston by 1 mm and raising the interior temperature to 27.40 c

One object has a mass of 1 kg and another object has a mass of 3 kg. if the speeds are the same, which of the following is true about their kinetic energy?

Two resistors r1 and r2 may be connected either in series or parallel across an ideal battery with emf ε. we desire the rate of energy dissipation of the parallel combination to be 8.75 times that of the series combination. if r1 = 105 ω, what are the (a) smaller and (b) larger of the two values of r2 that result in that dissipation rate?