Answer:
7] Force = mass × acceleration
Force = 2 × 5
<u>Force = 10 N</u>
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8] Velocity = acceleration due to gravity × time taken
Velocity = 9.8 × 12
<u>Velocity = 117.6 m/s</u>
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:
2.7 J
Explanation:
The energy of one photon is given by

where
h is the Planck constant
f is the frequency
For the photons in this problem,

So the energy of one photon is

The number of photons contained in 1.0 mol is
(Avogadro number)
So the total energy of
photons contained in 1.0 mol is
