What is the tensile strength of hair ?
2 answers:
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Explanation:
Mass of two soccer balls,
Initial speed of first ball,
Initial speed of second ball,
After the collision,
Final speed of the second ball,
(a) The momentum remains conserved. Using the conservation of momentum to find it as :
is the final speed of the first ball
(b) Let is the kinetic energy of the first ball before the collision. It is given by :
It is at rest, so, the kinetic energy of the first ball before the collision is 0.
(c) After the collision, the second ball comes to rest. So, the kinetic energy of the second ball after the collision is 0.
Hence, this is the required solution.
Answer:
The correct option is;
(c) 64W
Explanation:
Here we have the Coefficient Of Performance, COP given by
The heat change from 23° to 6°C for a mass of 10 kg/h which is equivalent to 10/(60×60) kg/s or 2.78 g/s we have
= m·c·ΔT = 2.78 × 4.18 × (23 - 6) = 197.39 J
Therefore, plugging in the value for in the COP equation we get;
which gives
Since we were working with mass flow rate then the power input is the same as the work done per second and the power input to the refrigerator = 63.674 J/s ≈ 64 W.
The power input to the refrigerator is approximately 64 W.