1.6 Acceleration Due To Gravity

Question 1

What is projectile motion?

Answer 1

Motion in a vertical plane

Projectile motion refers to the trajectory of an object that is thrown or projected into the air, affected by gravity.

Question 2

Define a projectile.

Answer 2

An object released or thrown into the air

Projectiles can include objects dropped from rest or thrown at various angles.

Question 3

What is the primary force acting on projectiles during motion?

Answer 3

Gravity

Gravity is the force that pulls projectiles back down to the ground after they have been thrown or released.

Question 4

What type of motion does a free throw in basketball exemplify?

Answer 4

Projectile motion

This is an example of motion where the ball is thrown into the air and follows a curved trajectory due to gravity.

Question 5

List examples of objects that experience motion in a vertical plane.

Answer 5

• Flipping a coin
• Punting a football
• A free throw in basketball

These actions involve objects moving upward or downward in a vertical motion.

Question 6

What happens in an amusement park ride based on acceleration due to gravity?

Answer 6

The ride transports thrill seekers upward and then releases them downward

This creates a thrilling experience as riders feel the effects of gravity during the descent.

Question 7

Fill in the blank: A projectile can be any object thrown into the air, including objects dropped from rest, objects thrown _______ or vertically upward.

Answer 7

[downward]

This includes various scenarios where projectiles are launched or fall due to gravity.

Question 8

True or False: All objects moving in a vertical plane are considered projectiles.

Answer 8

False

Only objects that are thrown into the air and affected by gravity are classified as projectiles.

Question 9

What dimensions does a plane have in relation to motion?

Answer 9

x (horizontal) and y (vertical)

These dimensions illustrate the two planes in which objects can move: horizontally and vertically.

Question 10

Who conducted experiments in the 16th century related to falling objects?

Answer 10

Galileo

Question 11

What did Galileo demonstrate about objects falling near Earth’s surface?

Answer 11

Objects have a constant acceleration

Question 12

What factor is neglected when discussing the acceleration of falling objects?

Answer 12

Air resistance

Question 13

What is the term for the acceleration experienced by objects due to Earth’s gravity?

Answer 13

Acceleration due to gravity

Question 14

Fill in the blank: The acceleration due to Earth’s gravity can be determined by performing a _______.

Answer 14

[specific experiment]

Question 15

What is the acceleration due to gravity?

Answer 15

9.81 m/s² [down]

This value is commonly used in physics to represent the acceleration experienced by an object in free fall near the Earth’s surface.

Question 16

What type of equations describe the motion of parabolas?

Answer 16

Quadratic equations

These equations include a power of two, such as y = x².

Question 17

What is the equation for the displacement of a vertical projectile?

Answer 17

Ad = Vi * t + (1/2) * a * t²

Where Ad is displacement, Vi is initial velocity, a is acceleration, and t is time.

Question 18

What was the height from which Vesna Vulovic fell?

Answer 18

10,160 m

She survived this fall when the DC-9 airplane she was on exploded.

Question 19

What is the initial velocity of a golf ball dropped from rest?

Answer 19

0 m/s

The ball starts from rest, hence its initial velocity is zero.

Question 20

How long does it take for a golf ball to fall from a height of 1.25 m?

Answer 20

0.505 s

This is the calculated time for the ball to reach the ground under the influence of gravity.

Question 21

The time it takes for an object to fall is directly proportional to what?

Answer 21

The square root of the height

This relationship holds true in free fall without air resistance.

Question 22

In the equation Ad = Vi * t + (1/2) * a * t², what does ‘Ad’ represent?

Answer 22

Displacement

‘Ad’ refers to the change in position of the object.

Question 23

True or False: The time it takes for a falling object to reach the ground depends on its mass.

Answer 23

False

The time only depends on the height from which it is dropped, not on the object’s properties.

Question 24

Fill in the blank: Without air resistance, the time it takes for a falling object to reach the ground depends only on the _______.

Answer 24

height from which it was dropped

This principle is fundamental in understanding free fall.

Question 25

What happens to velocity and acceleration when a ball is thrown upward?

Answer 25

Velocity decreases while acceleration is downward due to gravity ## Footnote The ball slows down as it moves upward.

Question 26

At what point does a thrown object reach its maximum height?

Answer 26

When its vertical velocity equals zero ## Footnote This occurs when the object momentarily stops at the top of its path.

Question 27

What causes the ball to speed up when falling back to the ground?

Answer 27

Acceleration due to gravity ## Footnote The acceleration is approximately 9.81 m/s² downward.

Question 28

What is the term for the motion of a ball thrown upward and falling back down?

Answer 28

Vertical projectile motion ## Footnote This encompasses both the upward and downward phases of the motion.

Question 29

In Stage 1 of the ball's motion, what is the relationship between velocity and acceleration?

Answer 29

Velocity and acceleration are in opposite directions ## Footnote This results in the ball slowing down.

Question 30

In Stage 2 of the ball's motion, what happens to the ball's acceleration?

Answer 30

The ball's acceleration is still 9.81 m/s downward ## Footnote This causes the ball to change direction after momentarily stopping.

Question 31

In Stage 3 of the ball's motion, what is the relationship between velocity and acceleration?

Answer 31

Velocity and acceleration are in the same direction ## Footnote This results in the ball speeding up.

Question 32

Fill in the blank: Juggling is an example of _______.

Answer 32

Projectile motion ## Footnote It illustrates the principles of motion under the influence of gravity.

Question 33

What is analyzed in Example 1.18?

Answer 33

The upward part of the motion of an object thrown upward ## Footnote It focuses on how the object behaves as it ascends.

Question 34

What is analyzed in Example 1.19?

Answer 34

The downward motion of the same object ## Footnote It examines the behavior of the object as it descends.

Question 35

What are the three stages of motion for a vertically projected ball?

Answer 35

1. Speed decreases 2. Speed becomes zero 3. Speed increases ## Footnote These stages correspond to the ball rising, reaching maximum height, and falling back down.

Question 36

What does the position-time graph of a ball thrown straight up illustrate?

Answer 36

Uniformly accelerated motion ## Footnote This refers to the constant acceleration due to gravity acting on the ball.

Question 37

In what year did the Krakatoa volcano erupt, and how high did it eject rocks?

Answer 37

1883; 55 km into the air ## Footnote The eruption was significantly powerful, estimated to be 10,000 times more powerful than the Hiroshima bomb.

Question 38

Why is the graph of a ball's motion a parabola rather than a straight vertical line?

Answer 38

Because the ball's motion is influenced by gravity, resulting in a parabolic path when plotted over time. ## Footnote The motion is actually vertical, but the position vs. time graph reflects the effects of acceleration.

Question 39

What is the best strategy for drawing tangents on a position-time graph to create a velocity-time graph?

Answer 39

Choose strategic points that begin and end a stage of motion ## Footnote These points define the stages and provide clear slopes for the tangents.

Question 40

What does a horizontal tangent on a position-time graph indicate?

Answer 40

The ball stopped momentarily ## Footnote A horizontal tangent has a slope of zero, indicating no change in position.

Question 41

What does the slope of a velocity-time graph represent?

Answer 41

Acceleration ## Footnote The slope indicates how velocity changes over time.

Question 42

Fill in the blank: The initial slope of the tangent on the position-time graph corresponds to a _______ velocity on the velocity-time graph.

Answer 42

positive (upward) ## Footnote This indicates that the ball is moving upward initially.

Question 43

Fill in the blank: The last tangent on the position-time graph has a _______ slope, corresponding to a final _______ velocity.

Answer 43

negative; negative ## Footnote This indicates the ball is falling back down.