Imagine that you have collided carts on an air-track to investigate conservation of momentum. your results show that momentum after a collision is usually a little less than the momentum before. which statement best explains your observation?
none of the listed answers are correct
the carts did not have enough mass.
momentum changed slightly due to friction.
kinetic energy was converted to gravitational potential energy.
the collisions were not perfectly elastic.

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?

In a series circuit the __ is the same at every point

The radius of an atom is closest in size to a