A carpenter is driving a 15.0-g steel nail into a board. His 1.00-kg hammer is moving at 8.50 m/s when it strikes the nail.
Half of the kinetic energy of the hammer is transformed into heat in the nail and does not flow out of the nail. What is the increase in temperature of the nail after the three blows that the carpenter needs to drive the nail in completely? The specific heat of steel is 448 J/kg K.
A) 8.1 K
B) 3.6 K
C) 1.8 K
D) 2.7 K
E) 7.7 K
Question 2
For what wavelength does a 100-mW laser beam deliver 1.6 1017 photons in one second? (c = 3.0 108 m/s, h = 6.626 10-34 J s)
A) 320 nm B) 340 nm C) 330 nm D) 350 nm