Answer:A block rests on a horizontal, frictionless surface. A string is attached to the block, and is pulled with a force of 45.0 N at an…
Explanation:
Answer:
Bill's motor power: W_B = F x S / T = F x 0.35 / 2= 0.175F
Nageen's motor power: W_N = F x S / T = F x 0.35 / 1.8 = 0.194F
=> 0.194F > 0.175F => Nageen's motor applied more power to the box than Bill's motor.
The answer is number two, number four, and number one
Answer:
Work out = 28.27 kJ/kg
Explanation:
For R-134a, from the saturated tables at 800 kPa, we get
= 171.82 kJ/kg
Therefore, at saturation pressure 140 kPa, saturation temperature is
= -18.77°C = 254.23 K
At saturation pressure 800 kPa, the saturation temperature is
= 31.31°C = 304.31 K
Now heat rejected will be same as enthalpy during vaporization since heat is rejected from saturated vapour state to saturated liquid state.
Thus,
=
= 171.82 kJ/kg
We know COP of heat pump
COP = 
= 
= 6.076
Therefore, Work out put, W = 
= 171.82 / 6.076
= 28.27 kJ/kg
Answer:
The spring was compressed the following amount:

Explanation:
Use conservation of energy between initial and final state, considering that the surface id frictionless, and there is no loss in thermal energy due to friction. the total initial energy is the potential energy of the compressed spring (by an amount
), and the total final energy is the addition of the kinetic energies of both masses:


