In the diagram, a force of 20 newtons is applied to a block. The block is in dynamic equilibrium. What is the magnitude and direction of the frictional force? A. 20 newtons in the direction of the applied force
B. 20 newtons opposite to the direction of the applied force
C. 20 newtons perpendicular to the direction of the applied force
D. 20 newtons in two directions, perpendicular and in the direction of the applied force
E. No friction is acting on the block.

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

Which features on mars point to the possibility of liquid water on the planet? impact craters with sharp rims volcanic cones with craters gullies and stream-like channels mountain ranges with faults

Which best describes the difference between internal and thermal energy?