A427 g glass coffee cup is at a room temperature of 20◦c. it is then plunged into hot dishwater at 84◦c. if the temperature of the cup reaches that of the dishwater, how much heat does the cup absorb? assume the mass of the dishwater is large enough so its temperature doesn’t change appreciably and the specific heat of glass is 840 j/kg · ◦ c. answer in units of j.

Explanation:

Given:

mass of glass cup,

initial temperature of glass,

final temperature of glass,

specific heat of glass,

So, the heat energy absorbed by the cup to reach the final temperature is given by:

where:

= change in temperature

gas and liquid

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.