In a machine, work output is less than work input because some energy is converted into thermal energy. true or false.

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

A15 ohm resistor and a 25 ohm resistor are connected in parallel to a 60 volt battery. what is the power used by each device

Abox that has self-contained cable clamps holds two light switches. a two-wire no. 12 cable with ground feeds the box, and a pair of two-wire no. 12 cables (four conductors) with ground wires leaves the box to feed the light fixtures. the second switch is fed by a no. 12 jumper wire from the first switch. which one of the following box combinations would furnish the minimum allowable volume? a. two 3-inch × 2-inch × 21⁄2-inch gangable device boxes b. two 3-inch × 2-inch × 11⁄2-inch gangable device boxes c. two 3-inch × 2-inch × 23⁄4-inch gangable device boxes d. two 3-inch × 2-inch × 21⁄4-inch gangable device boxes