What is the change in internal energy if 60 j of heat are added to a system
and the system does 40 j of work on its surroundings? use au = q-w.

The motor m applies a time-varying force of f (200 t) n, where t is in seconds. box b with mass 200 kg starts from rest, and the coefficients of kinetic and static friction are 0.2 and us 0.3 the acceleration due to gravity is g 9.8 m/s2 b 300 a) find the time ' when the box starts to move. b) calculate the speed of the crate at 3 s c) calculate the power delivered by the motor at t 3 s

Need people build a dam to create a reservoir that supplies water a nearby city needs. describe two ways this action will likely affect the water cycle in the local environment. (5 points) worth 20 points

A15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature changes from 25°c to 175°c. what is the specific heat capacity of iron?