Model rocket engines are rated by the impulse that they deliver when they fire. a particular engine is rated to deliver an impulse of 3.5 kg⋅m/s. the engine powers a 120g rocket, including the mass of the engine. part a what is the final speed of the rocket once the engine has fired? (ignore the change in mass as the engine fires and ignore the weight force during the short duration of the engine firing.)

Explain why the aperture of the spherical mirror should be small compared to the radius of curvature of the mirror.

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

A47.2 g block of copper whose temperature is 480 k is placed in an insulating box with a 91.8 g block of lead whose temperature is 200 k. (a) what is the equilibrium temperature of the two-block system? (b) what is the change in the internal energy of the two-block system between the initial state and the equilibrium state? (c) what is the change in the entropy of the two-block system? the heat capacities of copper and lead are 386 j/kg·k and 128 j/kg·k, respectively.