STANDARD 1a Students know position is defined in relation to some choice of a standard reference point and a set of reference directions

MOTION The position of an object is defined by a direction and distance from a reference point A reference point is a place or object used for comparison to define where something is. Objects that don’t move make good reference points An object is in motion if it changes position in relation to a reference point

MOTION 83. Which object would make the best reference point? A a flagpole B a mountain bike during a race C a bird in flight D a car moving slowly on the highway ANSWER: A

STANDARD 1b Students know that average speed is the total distance traveled divided by the total time elapsed and that the speed of an object along the path traveled can vary

That’s right-it’s traveling at 50 m/s MOTION Speed-amount of distance covered in a certain time 100 meters 2 seconds That’s right-it’s traveling at 50 m/s If the car covers a distance of 100 meters in 2 seconds what is its speed in m/s ?

MOTION 85. A truck traveled 180 km in 3 hours. What was the truck’s average speed? A 18 km/hr B 3 km/hr C 15 km/hr D 60 km/hr ANSWER: D

MOTION 86. What is the average speed of the object over the time interval 4 s to 8 s? A 2.0 m/s B 2.7 m/s C 3.0 m/s D 5.3 m/s ANSWER: C

MOTION 87. If a horse walked 50 m in 68 s, cantered 150 m in 35 s, and galloped 300 m in 22 s, what would its average speed be? A 0.25 m/s B 4 m/s C 6.22 m/s D 40 m/s ANSWER: B

STANDARD 1c Students know how to solve problems involving distance, time, and average speed

MOTION To find average speed of an object use: v = d/t velocity = distance divided by time To find distance traveled by an object use: d = vt distance = velocity times time To find time elapsed during the motion of an object use: t = d/v time = distance divided by velocity

MOTION 89. What is the time required for a cheetah to travel a distance of 120 m at an average speed of 3 m/s? A 360 s B 123 s C 40 s D 10 s ANSWER: C

MOTION 90. Kyle needs to determine the distance a car traveled given the car’s average speed and the time it took the car to travel the distance. What equation should Kyle use to determine distance? A d = vt B v = d/t C d = t/v D t = d/v ANSWER: A

STANDARD 1d Students know the velocity of an object must be described by specifying both the direction and the speed of the object

MOTION Velocity is speed in a given direction 40 miles per hour NORTH is a velocity because it indicates both speed and direction. Velocity is a vector because it has both magnitude and a direction The magnitude of the velocity vector is the speed

MOTION 91. What is a description of velocity? A 50 km/h B 50 km/h west C 50 km west D 50 km ANSWER: B

STANDARD 1e Students know changes in velocity may be due to changes in speed, direction, or both

MOTION An object changes its velocity if it changes its speed, its direction, or both Acceleration is the rate at which velocity changes with time Acceleration refers to increasing speed, decreasing speed, or changing direction

MOTION 92. A baseball pitcher throws a pitch that curves over the plate at a speed of 100 km/hr. The velocity of the baseball changed because the baseball A slowed down over home plate B never changed direction C could not be hit by the batter D changed direction during its motion ANSWER: D

MOTION 94. As a ball rolls down a hill, what happens to its speed and its acceleration? A speed and acceleration both increase B speed and acceleration both decrease C speed increases and acceleration stays constant D speed decreases and acceleration increases ANSWER: C

MOTION 95. An object that is moving at a constant speed will be accelerating if it is A moving in a straight line B moving in a curved line C moving away from you D moving toward you ANSWER: B

STANDARD 1f Students know how to interpret graphs of position versus time and graphs of speed versus time for motion in a single direction

GRAPHING MOTION CONSTANT SPEED Distance vs Time Velocity vs Time

CHANGING VELOCITY (ACCELERATION) GRAPHING MOTION CHANGING VELOCITY (ACCELERATION) Distance vs Time Velocity vs Time The distance you travel each second becomes longer and longer Plotting the velocity against time results in a positive slope

CHANGING VELOCITY (DECELERATION) GRAPHING MOTION CHANGING VELOCITY (DECELERATION) Distance vs Time Velocity vs Time

Forces and Motion 96. Over which time interval did the object accelerate? a. 2 s to 4 s b. 4 s to 6 s c. 6 s to 8 s d. 8 s to 10 s ANSWER: B

Forces and Motion 97. Over what time interval is the speed of the object constant? a. 0 s to 1 s b. 1 s to 2 s c. 2 s to 3 s d. 4 s to 5 s ANSWER: C

Forces and Motion 98. What is the speed of the car? A 1 km/min B 6 km/min C 10 km/min D 60 km/min ANSWER: A

Forces and Motion 100. What is the speed of the object during the time interval from 2 seconds to 5 seconds? A 0 m/s B 3 m/s C 12 m/s D 30 m/s ANSWER: A

MOTION 101. The graph represents the motion of an object. The slanted, straight line on the graph indicates that A the object is traveling at a constant speed B the object is not accelerating C the object is accelerating at a constant rate D the object is accelerating at an ever increasing rate ANSWER: C