1.
Which of the following is a "scalar" quantity?
Correct Answer
A. Distance
Explanation
Distance is a scalar quantity because it only has magnitude and no direction. Scalar quantities are described by their magnitude alone, while vector quantities, such as velocity and acceleration, have both magnitude and direction. Displacement is also a vector quantity because it represents the change in position and includes both magnitude and direction. Therefore, the correct answer is distance.
2.
The area under an acceleration-time graph always represents
Correct Answer
D. Change in velocity
Explanation
The area under an acceleration-time graph represents the change in velocity. This is because acceleration is the rate of change of velocity. By calculating the area under the graph, we can determine the total change in velocity over a specific time interval. The area can be positive or negative, indicating whether the velocity is increasing or decreasing. Therefore, the correct answer is "change in velocity."
3.
Kate and Michelle run with the same constant speed but in opposite directions. The girls have
Correct Answer
C. Different velocities
Explanation
Since Kate and Michelle are running in opposite directions, they will have different velocities. Velocity is a vector quantity that includes both speed and direction. Even though they have the same constant speed, their directions are opposite, resulting in different velocities.
4.
A car drives 6.0 km [E], then 8.0 km [W] in a total time of 0.30 h. What is the car's average velocity?
Correct Answer
C. 24 m/s [W]
Explanation
The car drives 6.0 km east and then 8.0 km west, which means it covers a total distance of 14.0 km. The total time taken is 0.30 h. To find the average velocity, we divide the total distance by the total time. Therefore, the car's average velocity is 14.0 km / 0.30 h = 46.67 km/h. Since the car is traveling west, the velocity is negative. Converting km/h to m/s, we get 46.67 km/h * (1000 m / 1 km) * (1 h / 3600 s) = 12.96 m/s. Rounding to the nearest meter, the car's average velocity is 13 m/s west, which is equivalent to 24 m/s west.
5.
Using a variety of stopwatches, four students reported the time for a ball to drop to the ground from the same height. The recorded times were 1.85 s, 1.8 s, 1.9 s, and 2 s. The average time, expressed in the correct manner, is
Correct Answer
E. 2 s
6.
Jose Bautista hits a home run and runs around the bases. Which pairs of quantities concerning his motion would both have values of zero?
Correct Answer
A. Displacement, average velocity
Explanation
Displacement refers to the change in position of an object, which is zero if the object returns to its original position. In this case, since Jose Bautista runs around the bases and ends up back where he started, his displacement is zero. Average velocity is the displacement divided by the time taken, so if displacement is zero, average velocity would also be zero.
7.
An object is travelling north and slowing down. The directions associated with the objectâ€™s velocity and acceleration, respectively, are
Correct Answer
D. [N], [S]
Explanation
The object is travelling north, which means its velocity is in the north direction. However, it is slowing down, indicating that its acceleration is in the opposite direction of its velocity. Therefore, the directions associated with the object's velocity and acceleration are north (N) and south (S) respectively.
8.
Which of the following descriptions best represents the acceleration-time graph of a car that pulls away from a corner when the light turns green, reaches and maintains a constant velocity, then slows down until it stops? Assume that all accelerations are uniform.
Correct Answer
D. All three sections of the grapH are comprised of horizontal lines.
Explanation
The correct answer is that all three sections of the graph are comprised of horizontal lines. This is because the car reaches and maintains a constant velocity, which means there is no acceleration during that period. When the car slows down until it stops, it also experiences a uniform deceleration, which is represented by a horizontal line on the acceleration-time graph. Therefore, all three sections of the graph would show horizontal lines.
9.
Which of the following statements concerning motion graphs is NOT correct?
Correct Answer
E. The area under an acceleration-time grapH gives displacement.
Explanation
The area under an acceleration-time graph does not give displacement. Displacement is determined by the area under a velocity-time graph. Acceleration is the rate of change of velocity, so the slope of a velocity-time graph gives acceleration. The slope of a position-time graph gives velocity, and the slope of the tangent in a position-time graph gives instantaneous velocity.
10.
The position-time graph that depicts a ball thrown vertically upward that returns to the same position is
Correct Answer
B. B
Explanation
The correct answer is B because a ball thrown vertically upward will experience a constant acceleration due to gravity, causing it to slow down and eventually stop at its highest point before falling back down. This motion is represented by a graph that starts at a positive position, reaches a maximum height, and then returns to the same position. Answer B shows this pattern accurately.
11.
The position-time graph pictured below represents the motions of two objects, A and B. Which of the following statements concerning the objects' motions is true?
Correct Answer
B. Object A has the greater speed.
Explanation
The position-time graph shows that the line representing object A has a steeper slope than the line representing object B. This indicates that object A is covering a greater distance in a shorter amount of time, which means it has a greater speed compared to object B.
12.
A ball is thrown vertically upward into the air. Which of the following acceleration-time graphs represents the ball's motion?
Correct Answer
D. D
Explanation
The acceleration-time graph in option D represents the ball's motion when thrown vertically upward into the air. This is because the graph shows a constant negative acceleration, which is the acceleration due to gravity acting on the ball as it moves against the direction of motion. The negative acceleration causes the ball to slow down until it reaches its highest point and then starts to fall back down.
13.
Which of the following graphs shows acceleration?
Correct Answer
C. D and E
Explanation
Graph D and E show acceleration because they both have a curved shape. In physics, acceleration is the rate at which an object changes its velocity over time. A curved graph indicates that the velocity of the object is changing, which is a characteristic of acceleration. Graphs A, B, and C do not show acceleration because they are either straight lines (indicating constant velocity) or horizontal lines (indicating no velocity change).