Which statement most accurately describes the second law of thermodynamics?

a. energy cannot be changed from one form to another without a loss of usable energy
b. one usable form of energy can be completely converted into another usable form.
c. energy cannot be created nor destroyed but it can be changed from one form to another.
d. energy cannot be created or destroyed.
e. energy cannot be transformed.

Anne applies a force on a toy car and makes it move forward. what can be said about the forces acting on the toy car at the moment anne applies the force?

A23 kg log of wood begins from rest, 300 m up a sluice (a water track used to transport logs, think of it as an inclined plane with negligible friction) inclined at 20° to the horizontal. after it reaches the flat waterway at the bottom it collides elastically with a 100 kg block of wood initially at rest near the base of the incline. (a) how long does it take the 23 kg log to travel down the incline? (b) what is the speed of the 23 kg log at the bottom of the incline? (c) what are the velocities of both blocks of wood after the collision? (d) what is the total kinetic energy before the collision? (e) what is the kinetic energy of the 23 kg log after the collision? (f) what is the kinetic energy of the 100 kg block of wood after the collision? (g) what is the total kinetic energy after the collision? (h) compare the total initial and total final kinetic energies. is this consistent with what you would expect for elastic collisions? explain!

Truck traveling west on the highway experiences an acceleration to the east. what could be the cause of this acceleration