 MCAS Physics Exams MCAS 2009 Session 1 Which of the following is the best example of work being done on an object? The diagram below shows the forces acting on a rock. The weight of the rock is 76 N. An upward force of 106 N is exerted on the rock. What is the net  force acting on the rock? 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 large spring is stretched horizontally between two people. One person wiggles the spring up and down at one end. The up‑and‑down vibration then moves along the spring to the other person. Which of the following types of wave is created in the spring? A simple circuit is shown in the diagram below. In which of the following circuits will bulb X have the same brightness as in the circuit above, if  all batteries and all light bulbs are identical? 6 Which of the following statements best describes the visible spectrum of light as seen by the human eye? To locate objects in their environments, bats in flight and porpoises under water both use ultrasound waves with frequencies that are beyond human hearing. These animals produce an ultrasonic wave and then detect echoes from nearby objects.

If a porpoise and a bat both produce ultrasonic waves when they are 16 m from an object, which animal would hear its echo first and why? The table below shows data from a heating experiment Which of the following conclusions is supported by the data in the table? Which of the following statements best explains why drops of liquid form on the outside of a glass of ice water on a hot day? Which of the following observations is a result of the Doppler effect? Electromagnetic waves of various frequencies reach Earth from distant parts of the universe. Which of the following can be inferred from this? 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 car has an oil drip. As the car moves, it drips oil at a regular rate, leaving a trail of spots on the road.

Which of the following diagrams of the car’s trail of spots shows the car continuously slowing down? The diagrams 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? Which of the following is an example of a vector quantity? Which of the following would be an advantage of using a 42 V battery in a car instead of a 12 V battery? A balloon is rubbed against a sweater. Which of the following occurs because of the rubbing? A toy cart that has a weight of 10 N moves with a constant velocity of 2 m/s to the right on a horizontal table. According to Newton’s laws of motion, which of the following statements is correct? The speed of sound in a particular gas is 900 m/s. A sound wave propagating in this material has a wavelength of 15 m. What is the frequency of this sound? Which of the following statements best describes an electromagnetic wave with a long wavelength? The figure below represents water in a flask being heated by a hot plate. Which of the following actions will slow down the rate of temperature increase of the water in the flask?

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 three questions. An attractive force is responsible for keeping satellites in orbit around Earth. The table below gives the masses of seven satellites and the distances between each of these satellites and the center of Earth. a.  Identify the attractive force that holds satellites in orbit.

 b.  Explain why satellite 3 does not experience the same amount of attractive force as satellite 1.

 c.  Identify one other satellite that experiences the same amount of attractive force as satellite 4, and explain why satellite 4 and the satellite you identified experience the same attractive force.

Refer to the following information for the next three questions. In the diagram below, shaded circles 1, 2, and 3 represent fixed charged objects, and circle 4 represents a charged object that is free to move. The magnitude of all the charges is equal.
 a.  Describe how charged objects 1, 2, and 3 will each affect object 4.

 b.  Compare the magnitude of the electric force between object 3 and object 4 with the magnitude of the electric force between object 2 and object 4.

 c.  Draw a diagram to show where object 4 will most likely move in relation to fixed objects 1, 2, and 3. Explain your answer.