/How much kinetic energy does an 80 kg man have while running at 1.5 m/s
1 answer:
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Answer:
The amount of energy required is
Explanation:
The energy required to convert the ice to steam is the sum of:
1) Energy required to raise the temperature of the ice from -20 to 0 degree Celsius.
2) Latent heat required to convert the ice into water.
3) Energy required to raise the temperature of water from 0 degrees to 100 degrees
4) Latent heat required to convert the water at 100 degrees to steam.
The amount of energy required in each process is as under
1)
where
' is specific heat of ice =
2) Amount of heat required in phase 2 equals
3) The amount of heat required to raise the temperature of water from 0 to 100 degrees centigrade equals
where
' is specific heat of water=
4) Amount of heat required in phase 4 equals
Thus the total heat required equals
Answer:
<em>The object-Earth system is open</em>
Explanation:
<u>Accelerated Motion </u>
When an object is released in free air (with no other forces than the gravity), it describes a free-fall motion and the formulas include the acceleration of gravity as part of the calculations. But when there is another external force, then the acceleration is not the gravity, but the result of the net force exerted on the mass of the object.
By definition, an open system includes the exchange of energy from and to the surroundings, that is why all systems surrounding our planet are considered as open systems. In our case, the object is interacting with the planet's gravity and there is some other external force, which will be computed later. The object-Earth system is open.
If the object starts from rest, its initial speed is zero, and
where a is the acceleration and t is the time. The distance traveled is given by :
From the two above equations, we find that:
Solving for a
It means the net force is
The object's weight is
This means there is some external force acting upwards delaying the object's fall of a magnitude of