Answer:
K = G Mm / 9R
Explanation:
Expression for escape velocity V_e =
Kinetic energy at the surface = 1/2 m V_e ²
= 1/2 x m x 2GM/R
GMm/R
Potential energy at the surface
= - GMm/R
Total energy = 0
At height 9R ( 8R from the surface )
potential energy
= - G Mm / 9R
Kinetic energy = K
Total energy will be zero according to law of conservation of mechanical energy
so
K - G Mm / 9R = 0
K = G Mm / 9R
Answer: The increase in temperature of the nail after the three blows is 8.0636 Kelvins. The correct option is (d).
Explanation:
Kinetic energy of the hammer ,K.E.=
Half of the kinetic energy of the hammer is transformed into heat in the nail.
Energy transferred to the nail in one blow =
Total energy transferred after 3 blows,Q =
Mass of the nail = 15 g = 0.015 kg
Change in temperature =
Specif heat of the steel = c = 448 J/kg K
The increase in temperature of the nail after the three blows is 8.1 Kelvins.Hence, correct option is (d).
Answer : The heat change of the cold water in Joules is,
Explanation :
First we have to calculate the mass of cold water.
As we know that the density of water is 1 g/mL. The volume of cold water is 45 mL.
Now we have to calculate the heat change of cold water.
Formula used :
where,
Q = heat change of cold water = ?
m = mass of cold water = 45 g
c = specific heat of water =
= initial temperature of cold water =
= final temperature =
Now put all the given value in the above formula, we get:
Therefore, the heat change of cold water is