Physical Science Take 10 Week #7

Day # 1 Question 1 Which of the following is an example of heat transfer by conduction? A. sunlight heating a floor B. an electric stove heating an iron pan C. a wood stove heating nearby objects through electromagnetic waves D. an electric heater heating air, which rises and is replaced with cooler air

Day # 1 Question 2 A student swings a bat horizontally, making contact with a ball thrown to her. The ball leaves the bat, and the bat continues moving through the rest of the swing. Which of the following statements describes the change in energy necessary to do work on the ball? A. All the kinetic energy of the bat is converted to work. B. All the potential energy of the bat is converted to work. C. Some of the kinetic energy of the bat is converted to work. D. Some of the potential energy of the bat is converted to work.

Day #1 Answers 1. Which of the following is an example of heat transfer by conduction? B. an electric stove heating an iron pan 2. A student swings a bat horizontally, making contact with a ball thrown to her. The ball leaves the bat, and the bat continues moving through the rest of the swing. Which of the following statements describes the change in energy necessary to do work on the ball? C. Some of the kinetic energy of the bat is converted to work.

Day # 2 Question 1 The diagram below represents a bicyclist at the top of a hill. Assume that the bicyclist does not apply the brakes as he rides down the hill. At which point will the bicyclist’s kinetic energy be closest to zero? A. point W B. point X C. point Y D. point Z

Day # 2 Question 2 Two full 2 L bottles of water are placed on a table. Bottle 1 was just removed from a refrigerator; bottle 2 is at room temperature. Which of the following statements describes the average molecular kinetic energy and the speed of the molecules in each bottle? A. Bottle 1 has the same average molecular kinetic energy as bottle 2, and the molecules have the same average speed in both bottles. B. Bottle 1 has a smaller average molecular kinetic energy than bottle 2, and the molecules have the same average speed in both bottles. C. Bottle 1 has a smaller average molecular kinetic energy than bottle 2, and the molecules have a slower average speed in bottle 1 than in bottle 2. D. Bottle 1 has a larger average molecular kinetic energy than bottle 2, and the molecules have a slower average speed in bottle 1 than in bottle 2.

Day #2 Answers 1. At which point will the bicyclist’s kinetic energy be closest to zero? A. point W 2. Which of the following statements describes the average molecular kinetic energy and the speed of the molecules in each bottle? C. Bottle 1 has a smaller average molecular kinetic energy than bottle 2, and the molecules have a slower average speed in bottle 1 than in bottle 2.

Day # 3 Question 1 A balloon is inflated with room-temperature air and then put in a sunny place. The balloon expands slightly due to a rise in temperature. Which of the following best describes the molecules of air inside the balloon when the balloon is left in the sunlight as compared to when it was first inflated? A. The molecules are moving faster. B. There are more molecules in the balloon. C. There are fewer interactions between the molecules. D. The molecules stop colliding with the walls of the balloon.

Day # 3 Question 2 A cup containing 25 mL of hot water and a similar cup containing 25 mL of cold water are placed on a table in a room at 21°C. Which of the following graphs shows the most likely change in temperature for each cup from 0 min to 40 min?

Day #3 Answers 1. Which of the following best describes the molecules of air inside the balloon when the balloon is left in the sunlight as compared to when it was first inflated? The molecules are moving faster. 2. Which of the following graphs shows the most likely change in temperature for each cup from 0 min to 40 min?

Day # 4 Question 1 Which of the following statements best explains why there is no change in temperature once thermal equilibrium between two objects in contact is reached? A. Heat can flow between two objects in contact. B. Heat does not flow between objects in contact at the same temperature. C. Heat does not flow spontaneously from a cooler object to a warmer object. D. Heat flows by conduction, convection, and radiation when the temperatures are the same.

Day # 4 Question 2 The diagram below show a man swinging a golf club. The kinetic energy of the golf club at point Y is more than the potential energy of the club at point X. Which of the following statements best explains why this fact does not violate the law of conservation of energy? A. Gravity is constant from point X to point Y. B. Air resistance is greater at point Y than at point X. C. Acceleration due to gravity is greater at point Y than at point X. D. Energy is added by the man to the golf club from point X to point Y. The diagram below show a man swinging a golf club.

Day #4 Answers 1. Which of the following statements best explains why there is no change in temperature once thermal equilibrium between two objects in contact is reached? B. Heat does not flow between objects in contact at the same temperature. 2. The kinetic energy of the golf club at point Y is more than the potential energy of the club at point X. Which of the following statements best explains why this fact does not violate the law of conservation of energy? D. Energy is added by the man to the golf club from point X to point Y.

Day # 5 Question 1 A student places four identically sized metal blocks on a hot plate at 80°C. Then the student places an identical piece of wax on top of each block, as shown in the diagram below. The student measures the time it takes for the piece of wax on each block to melt. Which of the following questions is being studied in this experiment? A. What is the melting point of the wax? B. What is the melting point of each metal? C. Which metal radiates heat the best? D. Which metal conducts heat the best?

Day # 5 Question 2 The figure represents a pendulum’s motion with the lowest point of its swing labeled P. What happens to most of the pendulum’s gravitational potential energy as it reaches the lowest point P? A. It is transformed into inertia. B. It is transformed into kinetic energy. C. It is transformed into thermal energy. D. It is transformed into chemical energy.

Day #5 Answers 1. Which of the following questions is being studied in this experiment? D. Which metal conducts heat the best? 2. What happens to most of the pendulum’s gravitational potential energy as it reaches the lowest point P? B. It is transformed into kinetic energy.