Physics: Acceleration and Motion

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Questions and Answers

What is the acceleration of an object falling freely near Earth's surface?

8.5 m/s²

9.8 m/s² (correct)

10.2 m/s²

9.5 m/s²

A car accelerates from rest at 2 m/s². How long would it take to reach a speed of 36 km/h?

12 s

18 s

15 s (correct)

10 s

What is the definition of acceleration?

Change in acceleration per unit time

Change in speed per unit time

Change in displacement per unit time

Change in velocity per unit time (correct)

A rocket accelerates from rest at 6 m/s² for 5 seconds. What is its final velocity?

30 m/s Signup and view all the answers

What is the deceleration of a plane landing on a runway?

6.25 m/s² Signup and view all the answers

What symbol is used to represent acceleration due to gravity?

g Signup and view all the answers

A runner accelerates from rest at 1.1 m/s² for 8.5 seconds. What is the runner's final velocity?

9.35 m/s Signup and view all the answers

A cheetah accelerates from 4.2 m/s to 120 km/h. What is the cheetah's acceleration?

9.5 m/s² Signup and view all the answers

What can be easily found from a velocity-time graph?

Acceleration and velocity Signup and view all the answers

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

Acceleration Signup and view all the answers

What is the acceleration of the plane if the velocity-time graph is linear?

Constant Signup and view all the answers

What is the motion of an object represented by a horizontal line on a velocity-time graph?

Constant velocity Signup and view all the answers

What does a negative slope on a velocity-time graph represent?

Deceleration Signup and view all the answers

What is the purpose of sketching a graph into shapes and finding the area of each shape?

To find the displacement Signup and view all the answers

What type of graph is used to easily find the position and velocity?

Position-time graph Signup and view all the answers

What is the acceleration of an object represented by a line with a constant slope on a velocity-time graph?

Constant Signup and view all the answers

How long does it take for the Mars rover, Curiosity, to travel 1 km?

7.14 hours Signup and view all the answers

What is the train's displacement after travelling 134 km?

134 km [E] Signup and view all the answers

What is the acceleration of a jet that travels 785 m [W] in 2.39 s?

3.29 m/s² [W] Signup and view all the answers

What is the rate of change of velocity?

Acceleration Signup and view all the answers

What is the horse's acceleration in Example 1?

2.2 m/s² [N] Signup and view all the answers

What is the unit of acceleration?

m/s² Signup and view all the answers

What is the direction of acceleration?

Same as the change in velocity Signup and view all the answers

What is required to solve an acceleration problem?

3 values Signup and view all the answers

Study Notes

Acceleration and Motion

Acceleration is the rate of change of velocity, describing how quickly an object's velocity changes.
Acceleration is a vector quantity, with both magnitude and direction.
The direction of acceleration is defined as the direction of the change in velocity.

Calculating Acceleration

The formula to calculate acceleration is: 𝑎⃑ = (∆𝑣⃑) / (∆𝑡)
To solve an acceleration problem, you need to know three values to solve for the fourth.

Units and Directions

Acceleration takes its direction from the change in velocity.
It is essential to define the positive direction to solve acceleration problems.
Key phrases like "from rest" or "to a stop" indicate the initial or final velocity.

Graphical Analysis

Position-time graphs and velocity-time graphs can be used to find position and velocity.
Acceleration can be easily found from the velocity-time graph.
A linear velocity-time graph indicates constant acceleration.

Example Problems

A cruise ship can accelerate at 0.01 m/s². To reach a speed of 25 km/h from rest, it would take a certain amount of time.
A runner can maintain a constant acceleration of 1.1 m/s² for 8.5 seconds. The distance covered can be calculated.
A plane lands and comes to a complete stop through 180 m of runway with a deceleration of 6.25 m/s². The initial velocity can be determined.
A cheetah can accelerate at a constant rate of 9.5 m/s². The time it takes to reach its top speed from an initial velocity can be calculated.

Gravity and Acceleration

Acceleration due to gravity is used frequently and is given the symbol g.
The average value of g is 9.8 m/s², but it can vary slightly around the world.

Motion and Velocity

A train travels at a certain speed, and its destination is a certain distance away. The time until it arrives can be calculated.
The Mars rover, Curiosity, has a maximum speed and can travel a certain distance in a certain time. The displacement can be calculated.
A jet travels a certain distance in a certain time, and its velocity can be calculated.

Graphical Representation

Position-time graphs, velocity-time graphs, and acceleration-time graphs can be used to represent motion.
The slope of a velocity-time graph relates to the acceleration.
Horizontal lines and lines with negative slopes can be used to describe motion.
The area under a velocity-time graph can be used to find the displacement.

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Description

Learn about acceleration, its formula, and how to calculate it. Understand the concept of acceleration as a vector quantity with magnitude and direction.