Kinematics Quiz 1. Two students argue over the differences between speed and velocity. One student says, “Speed is a vector because it describes how fast an object is traveling. Velocity is a scalar because it tells how fast and what direction an object is traveling.” Which of the following statements is correct? A. The student’s understanding of speed and velocity is correct but their understanding of scalar and vector is incorrect. B. The student’s understanding of speed and velocity is incorrect but their understanding of scalar and vector is correct. C. The student’s understanding of all four terms (speed, velocity, scalar, and vector) is incorrect. D. The student’s understanding of all four terms (speed, velocity, scalar, and vector) is correct. 2. Two students are conducting an experiment in which they are trying to find a relationship between the angle of incline of a ramp and the final speed a car reaches when rolling down the ramp. In order to collect their data, the students must determine the final speed of the car at the bottom of the ramp. The students discuss how they should determine this speed. Student 1: “We need to measure the length of the ramp and the time it takes the car to roll down it. Then we can divide the total distance by the total time to find the final speed.” What is wrong with Student 1’s method for determining final speed? A. This method does not account for the height of the ramp. B. This method does not take into account the angle of the ramp. C. This method will determine the acceleration, not the final speed. D. This method will only determine the average speed, not the final speed. 3. A cart moving across a level surface accelerates uniformly at 1.0 m/s 2 for 2s. What additional information is required to determine the distance traveled by the cart during this 2.0s interval? a. The amount of friction between the cart and the surface. b. The mass of the cart. c. The net force acting on the cart. d. The initial velocity of the cart. 4. Usain Bolt of Jamaica set a new world record during the Beijing Olympics for running the 100 meter dash in 9.58 seconds. What was his average speed and velocity during this race? A. Average speed was about 0.1 m/s; average velocity was 0 m/s B. Average speed was about 0.1 m/s; average velocity was about 0.1 m/s C. Average speed was about 10 m/s; average velocity was 0 m/s D. Average speed was about 10 m/s; average velocity was about 10 m/s 5. A student has asked the question: How are vectors and scalars different? She wants to make her question more specific. Which of the following questions would best help her find a difference between vectors and scalars? A. Do vectors and scalars have magnitude? B. Do vectors and scalars have direction? C. Do vectors and scalars have units? D. Do vectors and scalars have signs?
