Answer: The symbol representing  the result of a  gas expanding against a constant pressure is W
Explanation:
According to first law of thermodynamics, energy can neither be destroyed nor created but rather transferred to one place to another and converted to and from other energy forms.
The mathematical form of first law of thermodynamics is:

where  = change in internal energy
 = change in internal energy
q = heat absorbed or released
W = work  
P = pressure 
 = volume change
 = volume change 
Thus the changes in heat or work leads to change in internal energy.
 
        
             
        
        
        
In a particle accelerator a positron (C= +1.6 x 10-19) travels through a perpendicular magnet field with a magnitude
of 3.1 x 10-2 T. At what speed must the positron travel in order for it to experience a force of 4.75 x 10-14 N?
28. An alpha particle (2 protons and 2 neutrons) experiences a downward force of 2.9 x 10-14 N while traveling in a
magnetic field with a strength of 5.1 x 10-19 T pointing to the north. Find the speed of the particle and the direction
it must be traveling in.
29. Find the length of a wire if it experiences a .63N force when it travels through a magnetic field with a strength of
0.85T whilst carrying 5.0 amps of current.
30. A coil with 462 turns of wire, a total resistance of 36Ω , and a cross-sectional area of 0.25 m2
is positioned with its
plane perpendicular to the field of a powerful electromagnet. What average current is induced in the coil during the 0.37s
that the magnetic field drops from 3.1 T to 0.0 T?
31. A step-up transformer has a potential difference across the primary of 28 V and a potential difference across the
secondary of 3.0 × 104
V. There are 28 turns in the primary coil. How many turns are in the secondary?
32. A step-up transformer is used to create a potential difference of 1.6872 × 105
V across the secondary. The potentia
        
             
        
        
        
The faster car behind is catching up/closing the gap/gaining on 
the slow truck in front at the rate of (90 - 50) = 40 km/hr.
At that rate, it takes (100 m) / (40,000 m/hr) = 1/400 of an hour 
to reach the truck.
(1/400 hour) x (3,600 seconds/hour) = 3600/400 = <em>9 seconds</em>, exactly