Astudent drops two metallic objects into a 120-g steel container holding 150 g of water at 25°c. one object is a 206-g cube of copper that is initially at 88°c, and the other is a chunk of aluminum that is initially at 5.0°c. to the surprise of the student, the water reaches a final temperature of 25°c, precisely where it started. what is the mass of the aluminum chunk?

Mass of the aluminium chunk = 278.51 g

Explanation:

For an isolated system as given the energy lost and gains in the system will be zero therefore sum of all transfer of energy will be zero,as the temperature will also remain same

A specific heat formula is given as                  

Energy Change = Mass of liquid x Specific Heat Capacity x Change in temperature

                                       Q =  m×c×ΔT

                        Heat gain by aluminium + heat lost by copper  = 0    (1)

For Aluminium:

      Q =

      Q = m x 17.94 joule

For Copper:

       Q= 4996.53 Joule

from eq 1

     m x 17.94 = 4996.53

    Mass of the aluminium chunk = 278.51 g

c) up is the direction the magnetic force is acting on the charge.

not too sure thinking all accelerations are pointed down