The correct answer to the question is A) 0.5 Kg.
CALCULATION:
Before going to answer this question, first we have to understand the law of conservation of energy.
As per law of conservation of energy, the energy can neither be created nor be destroyed. It can only change from one form to another form and the total energy of universe is always constant.
As per the question, the stone was initially at a height of 2m from the ground.The energy possessed by the stone at this height is gravitational potential energy.
When the stone is released, the stone moves downward under gravity. It gains kinetic energy. When it just hits the ground, whole of its potential energy must have been converted into kinetic energy.
Hence, P.E at height 2m = K.E of the stone just before hitting the ground.
The potential energy of a body at a height h from the surface of earth is calculated as-
Potential energy P.E = mgh
Here, g is known as the acceleration due to gravity and its value is .
It is given that the height of the stone h = 2m.
The kinetic energy of the stone just before reaching ground K.E = 9.8 J.
We know- P.E of stone at height 2m = K.E of stone when it hits the ground.
⇒ mgh = 9.8 Joules
⇒ m =
=
= [ans]
Answer:
heat required in pan B is more than pan A
Explanation:
Heat required to raise the temperature of the substance is given by the formula
now we know that both pan contains same volume of water while the mass of pan is different
So here heat required to raise the temperature of water in Pan A is given as
Now similarly for other pan we have
So here by comparing the two equations we can say that heat required in pan B is more than pan A
Answer:
b) It is impossible to tell without knowing the masses.
Explanation:
The temperature change of a substance when it receives/gives off a certain amount of heat Q is given by
where
Q is the amount of heat
m is the mass of the substance
Cs is the specific heat capacity of the substance
In this case, we have a hot piece of aluminum in contact with a cold piece of copper: the amount of heat given off by the aluminum is equal to the amount of heat absorbed by the copper, so Q is the same for the two substances. However, we see that the temperature change of the two substances depends on two other factors: the mass, m, and the specific heat, Cs. So, since we know only the specific heat of the two substances, but not their mass, we can't tell which object will experience the greater temperature change.