Q1) If the amount of heat needed for 3kg of a material for a phase change is 300kJ, calculate the specific latent heat of 5 kg of that material. Show the work out. Q2) A metal block of mass 500g is heated from 30⁰C to 230⁰C, an electric heater was used for 2 minutes to raise the temperature of the block. The specific heat capacity of the metal is 0.5J/g⁰C. Find the power rating of the heater.

Air enters a compressor operating at steady state at 1.05 bar, 300 k, with a volumetric flow rate of 93 m3/min and exits at 12 bar, 400 k. heat transfer occurs at a rate of 15.5 kw from the compressor to its surroundings. assuming the ideal gas model for air neglecting kinetic potential energy effects, determine the power in put in kw.

Why do astronauts in the space shuttle weigh less?

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".