A knight sits on a castle wall during a siege. To while away time, he notes that boulders catapulted from below land on the top of his wall with a vertical velocity of 8.5 m/s. If he is 34 m above the catapult, what is an initial velocity of the boulders? The acceleration of gravity is 9.8 m/s2.

Question2

In a lab experiment you note than an object experiences a steady decrease in temperature with the passage of time. If that object is absorbing 100 units of radiant energy every second, what should be true about the amount it emits?

Describe the answer with reference to the concept of radiative equilibrium.