A horse pulls on a carriage. By Newton's third law, the carriage pulls back on the horse with equal force. Why do the action and reaction forces just described not balance each other out? A.
because this is not an action--reaction pair
B.
because action and reaction forces are not equal in magnitude in this case
C.
because action and reaction forces act in the same direction in this case
D.
because the action force acts on the carriage, while the reaction force acts on the horse

Air is held within a frictionless piston-cylinder container, which is oriented vertically. the mass of the piston is 0.45 kg and the cross-sectional area is 0.0030 m2. initially (state 1) the pressure of the gas is sufficient to support the weight of the piston as well as the force exerted by the atmospheric pressure ( 101.32 kpa). the volume occupied by the air within the cylinder in state 1 is 1.00 liter. one end of a spring (with spring constant k = 1000 n/m) is attached to the top of the piston, while the other end of the spring is attached to a stage that can move vertically. initially the spring is undeflected and therefore exerts no force. then the stage is then moved quasistatically downward a distance of 10.0 cm, at which point the system reaches state 2. the piston-cylinder is not insulated; rather it remains in diathermal contact with the surroundings, which are at a constant temperature of 300 k. what is the change of pressure within the container?

Orange juice has a lower or higher viscosity than chocolate syrup

If frequency goes down, what happens to wavelength? does it get shorter or longer?