Answers - 8th Grade Integrated ScienceMs. Uddo & Mrs ...



1. What is happening in the graph shown below?A.The object is moving at a constant speed away from the origin.B.The object is moving at a constant speed toward the origin.C.The object's speed is changing.D.The object is standing still.-381005187952. The graph below shows how the position of an object changes over time.Assuming that the motion of the object remains the same, at what speed will the object be traveling when it reaches a position of 6?m? A.5?m/sB.6?m/sC.1?m/sD.4?m/s3. Speed is the amount of distance that an object travels per unit timespeed=dtVelocity is speed with direction.Use this information to calculate the velocity of a truck that travels 2,200 kilometers in 21.5 hours from Texas to Georgia. A.0.01 km/hr westB.0.01 km/hr eastC.102.3 km/hr eastD.102.3 km/hr west4. A car is traveling south at a speed of 64 miles per hour and then begins traveling west but continues traveling at the same speed. Which of the following has changed? A.velocityB.gravityC.massD.speed-2476506381755. Chris drove his car to the movie theater. Look at the graph of Chris's speed over time, from when he left his house to when he arrived at the theater.At which times did Chris most likely stop at a stoplight? A.time = 3 min, time = 10.5 min, time = 12 minB.time = 2 min, time = 11 minC.time = 0 min, time = 21 minD.time = 1.5 min, time = 6 min, time = 14 min-1333503416306. What does the slope of this graph represent? A.the deceleration of a steel bobB.the positive acceleration of a steel bobC.the position of a steel bobD.the speed of a steel bob7. A car is traveling south at a speed of 54 miles per hour and then begins traveling at a speed of 55 miles per hour but continues traveling in the same direction. Which of the following has changed? A.velocityB.massC.volumeD.density8. The measure of an object's speed and direction is the object's ______. A.accelerationB.velocityC.momentumD.speed1581151485909. The above graph presents a vehicle's speed over the course of 14?minutes. According to the graph, the vehicle's speed is initially 10?mi/hr, and the speed peaks at 94?mi/hr after 14 minutes.How much distance did the vehicle cover in that time? A.11 milesB.2.5 milesC.12 milesD.84?miles10. Examine the diagram below.Which of the above objects is moving the fastest? A.CB.All 3 objects are moving at the same speed.C.AD.B11. The graph below shows how the position of an object changes over time.Assuming that the motion of the object remains the same, at what position will the object be when it has traveled for a total of 6?s? A.2 mB.0 mC.5 mD.1 m12. A graphical representation of a car's motion is shown below.What is happening to the car in the following graph?A.There is not enough information to determine the exact speed or the exact acceleration of the car.B.The car is accelerating at a changing rate of 12.5 m/s2 from O to P, driving at a constant acceleration of 25 m/s from P to Q, and decelerating at a changing rate of 8.3 m/s2 from Q to R.C.The car is accelerating at a constant rate of 12.5 m/s2 from O to P, driving at a constant speed of 25 m/s from P to Q, and decelerating at a constant rate of -8.3 m/s2 from Q to R.D.The car is accelerating at a constant rate of 25 m/s2 from O to P, standing still from P to Q, and decelerating at a constant rate of -25 m/s2 from Q to R.13. Which of the following graphs represents constant positive acceleration?A.WB.XC.YD.Z14. The graph below shows how the position of an object changes over time.Assuming that the motion of the object remains the same, where will the object be positioned when it has traveled for a total of 5?s? A.6 mB.4 mC.5 mD.1 m15. The graph below shows how the position of an object changes over time.Assuming that the motion of the object remains the same, at what speed will the object be traveling when it reaches a position of 1?m? A.6?m/sB.1?m/sC.0?m/sD.2?m/s16. Lauren rode the bus home from the mall on Saturday. She felt the bus accelerate as it left the parking lot, and then the bus turned right. The bus drove east on the freeway for five minutes before exiting, decelerating, and stopping at the stoplight. Then it turned left and slowed to a stop at the end of Lauren's street.All of these actions describe a change in velocity except A."she felt the bus accelerate".B."the bus drove east on the freeway for five minutes".C."it turned left and slowed to a stop".D."the bus turned right".17. Which of the following graphs represents a changing deceleration?-29527511430A.YB.ZC.XD.W18. Choose the best description of the motion of the object from t=4.0 s to t=9.0 s. A.The object is slowing down.B.The position of the object is not changing.C.The object is speeding up.D.The object is at a constant velocity.19. Which of the following graphs shows zero acceleration?A.ZB.YC.WD.X20. Which of the following determine an object's velocity? A.speed, direction, and accelerationB.speed and massC.direction and accelerationD.speed and directionAnswers1. A 2. C 3. C 4. A 5. B 6. B 7. A 8. B 9. C 10. C 11. B 12. C 13. A 14. C 15. B 16. B 17. B 18. A 19. D 20. D Explanations1. A straight, slanted line on any distance-time graph means that the object is moving at a constant speed. In this case, since the slope of the line is positive, the object is moving at a constant speed away from the origin.It is also possible to say that this object is moving at a constant positive velocity.2. The graph's vertical axis measures the object's distance in meters from a point of reference. The horizontal axis measures time in seconds.The slope of the line on a position vs. time graph represents speed.slope = rise / runThe graph shows that the object moves one meter away from the reference point every second (1?m/s). This motion is constant.Assuming that the motion of the object remains the same, it should be traveling at the same speed of 1?m/s when it reaches a position of 6?m.3. Velocity is a measurement that has both a magnitude and a direction.The magnitude of the velocity is calculated using the formula for speed.dt=2200 km21.5 hr=102.3 km/hrSince the truck is moving from Texas to Georgia, the direction of the truck is east.So, the velocity of the truck is 102.3 km/hr east.4. Velocity is a vector quantity. This means that an object's velocity is determined by not only its speed but also its direction. Therefore, if the direction the car is moving changes, then so does its velocity.5. Stopping at a stoplight means that Chris's speed would be zero on the graph. The times that his speed is zero are times t=0, t=2 min, t=11 min, and t=21 min. Because the graph shows his speed from the time he left his house (at t=0) to the time he arrived at the theater (at t=21 min), the most likely times he stopped at stoplights are times t=2 min and t=11 min.6. The velocity of the steel bob is increasing from t=0 s to t=11 s. Thus, the steel bob is accelerating (positive change in velocity over time).Graph found at . Velocity is a vector quantity. This means that an object's velocity is determined by not only its direction but also its speed. Therefore, if the car's speed changes, then so does its velocity.8. Velocity is a vector quantity. This means that an object's velocity is determined by not only its speed but also its direction.9. Notice that the speed is given in miles per hour, but the time is given in minutes. The slope of the graph is equal to the acceleration of the vehicle. In order to complete the calculation, however, the units need to be changed, as shown below.Convert from minutes to hours.Now the distance can be calculated as usual.10. On any distance-time graph, the object that has the line with the steepest positive slope will travel the greatest distance in the shortest amount of time and thus have the greatest speed.Since object A has the line with the steepest positive slope, object A is moving the fastest.11. The graph's vertical axis measures distance in meters from a point of reference. The horizontal axis measures time in seconds. The graph shows that the object moves one meter toward the reference point every second (1?m/s). This motion is constant.Assuming that the motion of the object remains the same, it can be predicted that the object will be at a position of 0?m (the point of reference) when it has traveled for a total of 6?s. This can be visualized by projecting the line of the graph farther until it intersects the point where the position value of 0?m meets the time value of 6?s.12. Since line segment OP is straight and has a positive slope, the car is accelerating at a constant rate of 12.5 m/s2 [(25 m/s - 0 m/s)/2 s] between points O and P.Since line segment PQ is straight and horizontal, the car has no acceleration during this time. Instead, the car moves at a constant velocity of 25 m/s for 4 seconds between points P and Q.Since line segment QR is straight and has a negative slope, the car is decelerating at a constant rate of -8.3 m/s2 [(0 m/s - 25 m/s)/3 s] between points Q and R.13. Graph W shows constant positive acceleration.A straight, slanted line with a positive slope on any velocity-time graph represents constant positive acceleration. Objects with constant positive acceleration speed up at a uniform rate.14. The graph's vertical axis measures the object's distance in meters from a point of reference. The horizontal axis measures time in seconds. The graph shows that the object moves one meter away from the reference point every second (1?m/s). This motion is constant.Assuming that the motion of the object remains the same, it can be predicted that the object will be positioned at 5?m when it has traveled for a total of 5?s. This can be visualized by projecting the line of the graph farther until it intersects the point where the position value of 5?m meets the time value of 5?s.15. The graph's vertical axis measures distance in meters from a point of reference. The horizontal axis measures time in seconds. The graph shows that the object moves one meter toward the reference point every second (1?m/s). This motion is constant.Assuming that the motion of the object remains the same, it will be traveling at the same speed of 1?m/s when it reaches a position of 1?m.16. A change in velocity can be a change in speed, a change in direction, or both. The only action by the bus that does not specifically mention a change in speed or direction is "the bus drove east on the freeway for five minutes".17. A curved line on any velocity-time graph represents a changing acceleration. If the line curves upward, the object is speeding up at a non-uniform rate. If the line curves downward, the object is slowing down or decelerating at a non-uniform rate.Therefore, graph Z shows changing deceleration.18. From t=4.0 s to t=9.0 s, the velocity of the object is decreasing, so the object is slowing down.Graph found at 19. A straight, horizontal line on any velocity-time graph represents zero acceleration or no acceleration. Therefore, graph X shows zero acceleration.20. Velocity is a vector quantity. This means that an object's velocity is determined by not only its speed but also its direction. ................
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