Answer:
The increase in temperature of the bullet is 351.1 kelvin
Explanation:
First, we should find the kinetic energy of the bullet is:
with m the mass and v the velocity.
Now we know that half of the kinetic energy of the bullet is transformed into internal energy, by second's law of thermodynamics that means heat (Q) to raise bullet temperature (T), so:
To know what the increase in temperature is, we should use specific heat of lead:
The equation that relates specific heat, change in temperature and mass is:
solving for 
:
Answer: 52%
Explanation:
1W = 1 J/s
motor input is 10000 J/s
Potential energy change
PE = 955(9.81)(25.0) = 234,213.75
power needed to change the PE in that time
P = 234,213.75/ 45 = 5,204.75 Watts
motor is 5204.75 / 10000 = 0.520475 or 52% efficient
Answer:
The mass of the rock is 
Explanation:
From the question we are told that
The length of the string is 
The angular velocity is 
The tension on the string is 
Generally the centripetal force acting on the rock is mathematically evaluated as
making m the subject of the formula
substituting values
