Given:
The thermal energy added to the system is Q = 90 J
The work done by the system on the surroundings is W = 30 J
To find the change in internal energy.
Explanation:
According to the first law of thermodynamics, the change in internal energy can be calculated by the formula

On substituting the values, the change in internal energy will be

Final Answer: The chage in internal energy is 60 J (option D)
 
        
             
        
        
        
Answer:
109656.25 Nm
Explanation:
 = Final angular velocity = 1.5 rad/s
 = Final angular velocity = 1.5 rad/s
 = Initial angular velocity = 0
 = Initial angular velocity = 0
 = Angular acceleration
 = Angular acceleration
t = Time taken = 6 s
m = Mass of disk = 29000 kg
r = Radius = 5.5 m

Torque is given by

The torque specifications must be 109656.25 Nm
 
        
             
        
        
        
We could use the change of pressure to calculate for the height climbed by the mountain hiker. The change of pressure is given by
p = rho * g * h, where p is the change of pressure, rho is the air density, g is the acceleration due to gravity, and h is the height.
Using the conversion 1 mbar = 100 Pa,
(930 - 780)(100) = (1.20)(9.80)h
15000 = 1.20*9.80*h
h = 1.28 km
        
             
        
        
        
the engine won't start or it sputters when it should be running perfectly. if the gasoline is old and stale, it will have lost a portion of its volatility. the lighter components of the gasoline (remember, gasoline is a mixture of different hydrocarbons) have probably evaporated off or disappeared.