While visiting the amusement park, Sarah and Sam choose to ride the bumper cars while their instructor records video of their collisions. Back in the classroom, the students analyze a head-on collision between Sarah and Sam’s two cars. The velocity of each car after the collision is equal to the velocity of the other car before the collision (i. e., the cars switch velocities). What can the students infer about the masses of the bumper cars?
A) Their masses are equal because both momentum and kinetic energy are conserved.
B) Their masses are unequal because both momentum and kinetic energy are conserved.
C) Their masses are unequal because neither momentum nor kinetic energy is conserved.
D) Their masses are unequal because neither momentum nor kinetic energy is conserved.

Jason is a body builder. despite being more fit, he weighs more than his brother ryan, who is the same height. which is a possible reason? a. jason has more muscle mass than ryan does. b. jason has more body fat than ryan does. c. jason has more muscle mass and body fat than ryan does d. jason has less body fat than ryan does.

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?

Ais useful when you need a simple machine to you separate two things. a. lever b. screw c. pulley d. wedge