 MCAS Physics Exams MCAS 2016 Session 2 The diagram below shows a pool with a length of 50 m. A person swims three lengths of the pool: from point X to point Y, from point Y to point X, and then from point X to point Y again. Which table shows the magnitudes of the distance the person traveled and the person’s final displacement? A television produces two types of waves: light and sound. Which of the following statements describes a property of both light and sound? What is the primary difference between insulators and conductors? Two identical objects, one hot and one cold, are placed near each other in a closed system. Which of the following graphs shows what happens to the temperatures of the objects over time? A student rides a bicycle down a hill and then up another hill without pedaling. Which of the following statements best describes what happens to the energy of the student and the bicycle while they move up the hill? A trumpet makes a low-pitched note, while a flute makes a high-pitched note. The volume of both notes is the same. What is different for the two sounds as they travel through the air? A book is dropped and falls to the floor. Which of the following describes the forces between the book and the floor when the book hits the floor? Electromagnetic radiation is used in many forms of communication. Electromagnetic waves with relatively long wavelengths are often used to transmit signals because  these waves travel easily around objects. Which type of electromagnetic radiation is best for transmitting signals around objects? A student lifts a weight to a certain height. Which of the following requires the student to do more work? Which of the following statements describes what happens when a sound wave moves from air into water? Which of the following circuits has the greatest current? The diagram below shows a top view of a glass aquarium filled with water. A laser pointer is aimed at the front of the aquarium at an angle. When the light from the laser initially hits the front of the aquarium, what is the most likely result? What is the net force that acts on a 5 kg object accelerating at 2 m/sec2? The graph below represents an object’s velocity over four time intervals: W, X, Y, and Z. During which time interval does the object have a positive acceleration? Which of the following statements illustrates a difference between static friction and kinetic friction? Which of the following diagrams represents the motion of particles in a transverse wave? A student builds a simple circuit and places a magnet under one of the circuit’s wires. When the switch is closed, charges flow in the circuit and the wire moves, as shown in the diagram below. Which question is the student most likely trying to answer? Which of the following describes a difference between electromagnetic waves and mechanical waves? Which of the following phenomena best explains why light changes direction when it passes through an eyeglass lens?

Open-Response Questions
• BE SURE TO ANSWER AND LABEL ALL PARTS OF THE QUESTION.
• If you do the work in your head, explain in writing how you did the work.

Refer to the following information for the next four questions. A car entering a highway stops on the entrance ramp. The car then accelerates uniformly along a straight line, reaching 28 m/sec in 5.6 seconds.
 a.  What is the average acceleration of the car during the 5.6 seconds? Show your calculations and include units in your answer.

 b.  How far does the car travel in the 5.6 seconds? Show your calculations and include units in your answer.

 c.  Traveling in a straight line, the car slows down uniformly from 28 m/sec, taking 3.5 seconds to come to a stop. What is the car’s average acceleration during the 3.5 seconds? Show your calculations and include units in your answer.

 d.  How far does the car travel during the 3.5 seconds it takes to stop? Show your calculations and include units in your answer.

Refer to the following information for the next four questions. During cold periods, many orange growers repeatedly spray their trees with water to prevent the oranges from freezing. If the air is cold enough, the sprayed water freezes around the oranges, leaving the oranges themselves unfrozen.
 a. Identify a measurement tool that orange growers use to measure the average kinetic energy of the air.

 b. Describe what happens to the average molecular kinetic energy of the sprayed water as it cools before it freezes.

 c. Describe what happens to the average molecular kinetic energy of the sprayed water as it freezes.

 d. Explain how the phase change of the sprayed water may protect the oranges from freezing.

Refer to the following information for the next four questions. An astronaut and his space suit have a combined mass of 157 kg. The astronaut is using a 5.0 kg tool kit to repair a solar panel on the International Space Station. When the tether connecting the astronaut to the space station becomes unattached, the astronaut, still holding the tool kit, starts to float away at 0.2 m/sec.
 a. Calculate how far from the space station the astronaut will be after 1 minute. Show your calculations and include units in your answer.

 b. Calculate the momentum of the astronaut holding the tool kit as the astronaut floats away. Show your calculations and include units in your answer.

 The astronaut decides the only way to change his motion and move back toward the space station is to throw the tool kit. c. Identify the direction the astronaut must throw the tool kit: toward the space station or away from it. Use the law of conservation of momentum to explain how throwing the tool kit may return the astronaut to the space station.

 d. Calculate the velocity with which the astronaut must throw the tool kit in order to float back toward the space station at 0.1 m/sec. Show your calculations and include units in your answer.