A body mass 10 kg falls to the ground from a height 1km . if all energy is converted to heat , find the amount of heat developed .
Answers
Answer:
To solve this question, we need to find the total mechanical energy, which will be equal to the potential energy of the mass. Since all the mechanical energy is lost into heat, so heat produced will be equal to this energy.
The formula used in solving this question is
⇒P.E.=mgh, where P.E. is the potential energy of a body of mass m at a height h.
⇒1cal=4.2J
Explanation:
Complete step by step answer
As the body is falling from the given height, its potential energy at the topmost point is given by
⇒P.E.=mgh
According to the question, m=5kg and h=30m
⇒P.E.=5(9.8)(30)
∴P.E.=1470J
As the body falls downwards, it starts gaining kinetic energy and losing potential energy.
Since there is no external force acting on the body except for the conservative gravitational force, the loss in potential energy at every point equals the gain in kinetic energy.
Therefore, the total mechanical energy of the body remains constant throughout the fall.
Hence, the total mechanical energy E equals the initial potential energy of the body.
∴E=1470J
Now, according to the question, all of this mechanical energy is lost into heat.
So the heat produced H will be equal to the total mechanical energy of the body, which is given as
⇒H=1470J
As the options have the energies in the unit of calories, we need to convert this energy into an equivalent amount of calories.
We know that 1cal=4.2J
Which means 1J=14.2cal
Therefore, 1470J=14704.2cal
Or, H=350cal
Thus, the heat generated is equal to 350cal
Hence the correct answer is option (A), 350cal.
Answer:
If a 10 kg body falls to the ground from a height of 15 m and if all its mechanical energy is convetred into heat the heat produced will be : (5 = 4.2 J/cal)