of water from 20"C to 100"C? A) 2 m B) 12 m C) 22 m D) 32 m 8. How much heat is needed to melt 16.50 kg of silver that is initially at 20 C? 13. During exercise, a person may give off 180 kcal of heat in 30 min by evaporation of water from the skin. How much water has been lost? 14. A 70-g bullet traveling at 250 m/'s penetrates a block of ice at 0"C and comes to rest within the ice. Assuming that the temperature of the bullet doesn't change appreciably, how much ice is melted as a result of the collision? a. Specific heat cap. of ice and water: 2.100 kJ/kg.C' &4186 kJ/kg.C' respectively b. Latent heat of fusion and vaporization for water: 333 kJ/kg & 2260 kJ/kg respectively 15. Equal masses of water at 20"C and 80"C are mixed. Calculate the final temperature of the mixture if there is no loss of heat? 16. What amount of heat must be taken from 450 g of steam at 106 "C to bring it to ice at 0 .C? 17. If heat is produced by a hotplate at the rate of 350 Watt, what amount of ice at 0 .C can it melt in 15 minutes?. 18. A metal rod had its length increased by 2 % when the temperature increased by 100"C. Calculate the coefficient of linear expansion of this rod. 19. The operating temperature of a heat engine is 470-C and 270-C. What is the theoretical maximum efficiency of such an engine? 20. A tyre is filled with air at 30 'C and the pressure gauge has a reading of 230k Pa. If after driving the tyre reaches a temperature of 45 'C calculate: a. The new gauge pressure of the tyre. b. The percentage of the air to be removed if the original pressure of 230 K Pa is to be obtained