Physical Science Module 9
Introduction to the Physics of Motion
Questions and Answers
- 1.
A point against which position is measured is called:
- A.
Vector Point
- B.
Acceleration Point
- C.
Reference Point
- D.
Position Point
Correct Answer
C. Reference PointExplanation
A point against which position is measured is called a reference point. This point serves as a starting point or a fixed location from which the position of an object can be measured or compared. It provides a frame of reference for determining the position, distance, or displacement of an object in relation to it. The reference point is essential in accurately describing the location or movement of an object in physics and other scientific disciplines.Rate this question:
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- 2.
A physical measurement that contains directional information is called:
- A.
Vector Quantity
- B.
Scalar Quantity
- C.
Directional Quantity
Correct Answer
A. Vector QuantityExplanation
A physical measurement that contains directional information is called a vector quantity. Unlike scalar quantities, which only have magnitude, vector quantities have both magnitude and direction. Examples of vector quantities include displacement, velocity, and force.Rate this question:
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- 3.
A physical measurement that does not contain directional information is called:
- A.
Vector Quantity
- B.
Scalar Quantity
- C.
Directional Quantity
Correct Answer
B. Scalar QuantityExplanation
A physical measurement that does not contain directional information is called a scalar quantity. Scalar quantities only have magnitude and no direction associated with them. Examples of scalar quantities include temperature, mass, time, and speed. Unlike vector quantities, which have both magnitude and direction, scalar quantities can be fully described by a single numerical value.Rate this question:
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- 4.
The time rate of change of an object's velocity is called:
- A.
Acceleration
- B.
Speed
- C.
Direction
- D.
Free Fall
Correct Answer
A. AccelerationExplanation
Acceleration is the correct answer because it refers to the time rate of change of an object's velocity. In other words, it measures how quickly an object's velocity is changing over time. Acceleration can be positive, negative, or zero, depending on whether the object is speeding up, slowing down, or maintaining a constant velocity.Rate this question:
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- 5.
The motion of an object when it is falling solely under the influence of gravity is called:
- A.
Acceleration
- B.
Speed
- C.
Direction
- D.
Free Fall
Correct Answer
D. Free FallExplanation
Free fall refers to the motion of an object when it is only influenced by gravity, with no other forces acting upon it. In this case, the object is not experiencing any resistance or air drag, causing it to accelerate downwards at a constant rate. The term "free fall" is used to describe this specific type of motion, distinguishing it from other forms of motion where additional forces are present.Rate this question:
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- 6.
Why must one use a reference point to determine whether or not an object is in motion?
- A.
It allows you to determine whether or not position changes.
- B.
So one can know where to start.
- C.
Motion depends on direction.
- D.
Reference point will show the speed of the motion.
Correct Answer
A. It allows you to determine whether or not position changes.Explanation
Using a reference point is necessary to determine whether or not an object is in motion because it provides a fixed point of comparison. By observing the position of the object relative to the reference point, one can determine if there is any change in position over time. Without a reference point, it would be difficult to establish whether the object is stationary or moving. The reference point serves as a starting point or a frame of reference for analyzing the motion of the object.Rate this question:
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- 7.
After a visit to your grandmother's house, you get in your car to go home. You are in the front passenger's seat and your mother is driving. As you back out of your grandmother's driveway, she stands outside, waving good-bye. Who is in motion relative to you?
- A.
You
- B.
Your mother
- C.
Your Grandmother
Correct Answer
C. Your GrandmotherExplanation
Your grandmother is in motion relative to you. As you are in the front passenger's seat of the car, you are stationary. Your mother is driving the car, so she is also stationary relative to you. However, as your grandmother stands outside and waves goodbye, she is moving away from you and the car, making her the one in motion relative to you.Rate this question:
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- 8.
After a visit to your grandmother's house, you get in your car to go home. You are in the front passenger's seat and your mother is driving. As you back out of your grandmother's driveway, she stands outside, waving good-bye. Who is motionless relative to you?
- A.
You
- B.
Your mother
- C.
Your grandmother
Correct Answer
B. Your motherExplanation
Your mother is motionless relative to you because you are in the front passenger's seat and she is driving the car.Rate this question:
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- 9.
How many miles per hour does a car travel if it makes a 40-mile trip in 30 minutes? (Please set up your problem using the correct formula and do your work on a sheet of paper, not in your head! :))
- A.
20 mph
- B.
40 mph
- C.
60 mph
- D.
80 mph
Correct Answer
D. 80 mphExplanation
To find the speed of the car in miles per hour, we need to convert the time from minutes to hours. Since there are 60 minutes in an hour, 30 minutes is equal to 30/60 = 0.5 hours.
Next, we divide the distance traveled (40 miles) by the time taken (0.5 hours) to get the speed.
40 miles / 0.5 hours = 80 mph.
Therefore, the car travels at a speed of 80 mph.Rate this question:
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- 10.
What is the velocity of a bicycle (in meters per second) if it travels 1 kilometer west in 4.1 minutes? (Please set up your problem using the correct formula and do your work on a sheet of paper, not in your head! :))
- A.
68.35 m/s west
- B.
0.41 m/s east
- C.
4.07 m/s west
- D.
40.65 m/s east
Correct Answer
C. 4.07 m/s westExplanation
To find the velocity of the bicycle, we need to convert the distance traveled and the time taken to the same units.
First, we convert 1 kilometer to meters by multiplying it by 1000 (1 km = 1000 m).
Next, we convert 4.1 minutes to seconds by multiplying it by 60 (1 minute = 60 seconds).
Now, we can use the formula velocity = distance/time.
Plugging in the values, we get velocity = 1000 m / (4.1 min * 60 s/min).
Simplifying, velocity = 1000 m / 246 s.
Calculating this, we get velocity = 4.065 m/s.
Since the bicycle is traveling west, the velocity is negative. Therefore, the correct answer is 4.07 m/s west.Rate this question:
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- 11.
You are looking in a scientist's lab notebook and find the following unlabeled measurement. Determine what physical quantity the scientist was measuring: 12.1 meters per second
- A.
Acceleration
- B.
Distance
- C.
Speed
- D.
Velocity
Correct Answer
C. SpeedExplanation
The scientist was measuring speed because the measurement of 12.1 meters per second represents the rate at which an object is moving in a specific direction. Speed is a scalar quantity that only considers the magnitude of the motion, without regard to the direction. This measurement does not provide any information about the change in direction or the rate at which the velocity is changing, which would be relevant for acceleration or velocity measurements.Rate this question:
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- 12.
You are again looking in this scientist's lab notebook and again you find the following unlabeled measurement. Determine what physical quantity the scientist was measuring: 31.2 feet
- A.
Acceleration
- B.
Distance
- C.
Speed
- D.
Velocity
Correct Answer
B. DistanceExplanation
The scientist was measuring distance because the measurement provided is in feet, which is a unit commonly used to measure distance. Acceleration, speed, and velocity are typically measured in units such as meters per second squared, meters per second, and meters per second in the metric system.Rate this question:
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- 13.
For a third time, you look in the scientist's lab notebook and find another unlabeled measurement. Determine what physical quantity the scientist was measuring: 14 millimeters per hour to the west
- A.
Acceleration
- B.
Distance
- C.
Speed
- D.
Velocity
Correct Answer
D. VelocityExplanation
The scientist was measuring velocity. Velocity is a vector quantity that describes the rate of change of an object's position with respect to time and includes both the magnitude (speed) and direction. In this case, the measurement of 14 millimeters per hour to the west indicates both the speed and the direction of the object's motion, making it a measurement of velocity.Rate this question:
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- 14.
You are getting tired of looking in this scientist's lab notebook, but you decide to look one more time just for the fun of it and find the last unlabeled measurement. Determine what physical quantity this scientist was measuring: 4.5 yards per minute (squared) north
- A.
Acceleration
- B.
Distance
- C.
Speed
- D.
Velocity
Correct Answer
A. AccelerationExplanation
The scientist was measuring acceleration. Acceleration is the rate at which an object changes its velocity over time. In this case, the measurement of 4.5 yards per minute (squared) north indicates a change in velocity over time in the north direction. The unit of yards per minute (squared) represents acceleration, as it combines both distance and time.Rate this question:
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- 15.
An eagle swoops down to catch a baby rabbit. Luckily for the rabbit, he sees the eagle and runs. An all-out chase ensues with the rabbit running east at 5.4 meters per second and the eagle pursuing at 4.4 meters per second. What is the relative velocity of predator and prey? (Please set up your problem using the correct formula and do your work on a sheet of paper, not in your head! :))
- A.
9.8 m/s away from each other
- B.
1.0 m/s away from each other
- C.
1.23 m/s toward each other
- D.
0.81 m/s away from each other
Correct Answer
B. 1.0 m/s away from each otherExplanation
The relative velocity of the predator (eagle) and prey (rabbit) can be found by subtracting the velocity of the prey from the velocity of the predator. In this case, the predator is chasing the prey, so the relative velocity would be the velocity of the predator minus the velocity of the prey. Therefore, the relative velocity of the predator and prey is 4.4 m/s - 5.4 m/s = -1.0 m/s. The negative sign indicates that the predator and prey are moving away from each other, so the correct answer is "1.0 m/s away from each other."Rate this question:
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- 16.
The acceleration of an object that moves with constant velocity is zero.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
When an object moves with constant velocity, it means that its speed and direction remain unchanged. Since acceleration is the rate of change of velocity, if the velocity is constant, then there is no change in velocity and therefore the acceleration is zero. This is because acceleration measures how much the velocity of an object is changing over time, and if there is no change, then the acceleration is zero.Rate this question:
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- 17.
A skier reaches the bottom of a slope with a velocity of 12 meters per second north. If the skier comes to a complete stop in 3 seconds, what was her acceleration? (Please set up your problem using the correct formula and do your work on a sheet of paper, not in your head! :))
- A.
36 m/s (squared) north
- B.
-36 m/s (squared) south
- C.
4 m/s (squared) south
- D.
-4 m/s (squared) north
Correct Answer
C. 4 m/s (squared) southExplanation
The skier starts with a velocity of 12 m/s north and comes to a complete stop in 3 seconds. To find the acceleration, we can use the formula: acceleration = (final velocity - initial velocity) / time. The final velocity is 0 m/s (since the skier comes to a stop), the initial velocity is 12 m/s north, and the time is 3 seconds. Plugging these values into the formula, we get: acceleration = (0 - 12) / 3 = -4 m/s^2. Since the skier is moving in the opposite direction of the initial velocity, the acceleration is in the opposite direction as well, which is south. Therefore, the correct answer is 4 m/s^2 south.Rate this question:
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- 18.
A car goes from 0 to 60 miles per hour north in 5 seconds. What is the car's acceleration? (Please set up your problem using the correct formula and do your work on a sheet of paper, not in your head! :))
- A.
300 miles/hour (squared) north
- B.
431.65 miles/hour (squared) south
- C.
30,000 miles/h (squared) south
- D.
43,165 miles/h (squared) north
Correct Answer
D. 43,165 miles/h (squared) northExplanation
The car's acceleration can be calculated using the formula:
Acceleration = (Final Velocity - Initial Velocity) / Time
In this case, the car starts from rest (0 mph) and reaches a final velocity of 60 mph in 5 seconds. Plugging these values into the formula:
Acceleration = (60 mph - 0 mph) / 5 s = 12 mph/s
However, the answer options are given in miles per hour squared. To convert mph/s to mph^2, we need to multiply by the conversion factor of 3600 (since there are 3600 seconds in an hour):
Acceleration = 12 mph/s * 3600 s/h = 43,200 mph^2
Therefore, the car's acceleration is 43,200 miles/hour (squared) north.Rate this question:
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- 19.
A person standing on a bridge over a river holds a rock and a ball in each hand. He throws the ball down towards the river as hard as he can and at the same time simply drops the rock. After both have left the person's hand, does one have a greater acceleration? If so, which one?
- A.
Yes, the ball will have a greater acceleration because he threw it as hard as he could.
- B.
Yes the rock will have a greater acceleration because it is more dense than the ball.
- C.
No, neither one has greater acceleration.
Correct Answer
C. No, neither one has greater acceleration.Explanation
Both the ball and the rock experience the same acceleration. The acceleration of an object is determined by the force acting on it, which in this case is the force of gravity. Since both objects are dropped from the same height and experience the same gravitational force, they will have the same acceleration. The initial velocity at which the ball was thrown does not affect its acceleration.Rate this question:
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- 20.
A physics student climbs a tree. To measure how high she has climbed, she drops a rock and times its fall. It takes 1.3 seconds for the rock to hit the ground. How many feet has she climbed? (Please set up your problem using the correct formula and do your work on a sheet of paper, not in your head! :))
- A.
20.8 feet
- B.
27.04 feet
- C.
41.6 feet
- D.
54.08 feet
Correct Answer
B. 27.04 feetExplanation
The formula to calculate the height climbed by the student can be derived from the equation of motion for free fall: h = (1/2)gt^2, where h is the height, g is the acceleration due to gravity (approximately 32 ft/s^2), and t is the time of fall. Plugging in the given values, we get h = (1/2)(32)(1.3)^2 = 27.04 feet. Therefore, the student has climbed 27.04 feet.Rate this question:
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