A 50 gram cart is connected to a spring whose unstretched length is 10 cm and whose spring constant is 2.5 N/cm. The motion of the mass is initiated by a person pulling the mass 5 cm to the right of its equilibrium position and releasing it. Ignore friction and air resistance in this problem. At the time the situation occurs, indicate whether the force vector requested points left (L), right (R), or has magnitude zero (0).

a. The force on the mass exerted by the spring when the mass is at its equilibrium position and is at rest. b. The force on the mass exerted by the spring when the mass is at its equilibrium position and is moving downward. c. The net force on the mass when the mass is at its equilibrium position and moving downward. d. The force on the mass exerted by the spring when it is at the top of its oscillation. e. The net force on the mass when it is at the top of its oscillation.

To understand the behavior of the electric field at the surface of a conductor, and its relationship to surface charge on the conductor. a conductor is placed in an external electrostatic field. the external field is uniform before the conductor is placed within it. the conductor is completely isolated from any source of current or charge. part a: which of the following describes the electric field inside this conductor? it is in the same direction as the original external field.it is in the opposite direction from that of the original external field.it has a direction determined entirely by the charge on its surface.it is always zero. part b: the charge density inside the conductor is: 0non-zero; but uniformnon-zero; non-uniforminfinite part c: assume that at some point just outside the surface of the conductor, the electric field has magnitude e and is directed toward the surface of the conductor. what is the charge density η on the surface of the conductor at that point? express your answer in terms of e and ϵ0

Acalorimeter uses the principle that thermal energy flows from hotter material to colder material until both reach the same

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.