Physics: Speed, Velocity, and Acceleration Key Concepts

What is speed?

Speed measures how fast an object changes its position, calculated as distance travelled divided by time taken.

What is the formula for calculating speed?

speed = distance (m) / time (s)

What are the units of speed?

Metres per second (m/s)

What is displacement?

Displacement is the distance travelled in a specific direction, representing the change in position from start to finish.

How does displacement differ from distance?

Displacement considers only the starting and finishing positions, while distance measures the total path travelled.

What is velocity?

Velocity is speed in a given direction, requiring both speed and direction to be fully described.

What is the formula for calculating velocity?

velocity = change in displacement (m) / time taken (s)

How does speed differ from velocity?

Speed only indicates how fast something is moving, while velocity includes the direction of movement.

What does a steep slope on a distance-time graph indicate?

A steep slope indicates high speed, as more distance is covered in less time.

What does a horizontal line on a distance-time graph represent?

A horizontal line indicates zero speed, meaning the object has stopped.

What does a downward slope on a distance-time graph signify?

A downward slope indicates negative speed, meaning the object is moving back towards the starting point.

How do you calculate speed from a distance-time graph?

Speed is calculated as the change in distance divided by the change in time between two points on the graph.

What happens to the slope of a distance-time graph when an object accelerates?

The slope becomes steeper as the object covers more distance in less time.

What should you always check before calculating speed?

Ensure that units are correct; convert distance to metres and time to seconds if necessary.

What does a gentle slope on a distance-time graph indicate?

A gentle slope indicates low speed, as less distance is covered in the same time.

What is the importance of direction in velocity?

Direction is crucial in velocity as it differentiates it from speed, which does not include direction.

What is the purpose of a motion sensor in measuring the speed of a trolley?

To measure the distance from the trolley at regular time intervals.

How can speed be calculated from a graph?

By calculating the slope of the distance-time graph.

What is acceleration?

The change in velocity in one second; it measures how quickly velocity changes over time.

What is the formula for acceleration?

acceleration = change in velocity / time taken.

What are the units of acceleration?

Metres per second squared (m/s²).

What does positive acceleration indicate?

The velocity is increasing (speeding up).

What does negative acceleration indicate?

The velocity is decreasing (slowing down), also known as deceleration.

How do you calculate acceleration from a velocity-time graph?

By calculating the slope of the graph: acceleration = change in velocity / change in time.

What does a horizontal line on a velocity-time graph represent?

Constant velocity (zero acceleration).

What happens to the velocity of a falling object due to gravity?

It increases by approximately 10 m/s every second.

What is the acceleration due to gravity on Earth?

Approximately 10 m/s².

How does air resistance affect falling objects?

It opposes motion, causing objects like feathers to fall more slowly than denser objects.

What is the difference in falling rates between objects in air and in a vacuum?

In a vacuum, all objects fall at the same rate regardless of mass; in air, air resistance affects their fall.

What does a steeper slope on a velocity-time graph indicate?

Greater acceleration.

What is the relationship between distance and time in a distance-time graph?

The slope indicates speed; steeper slopes mean faster speeds.

What does displacement refer to?

Distance in a given direction, depending only on starting and finishing positions.

What is the formula for speed?

speed = distance / time.

What is the formula for velocity?

velocity = change in displacement / time taken, including direction.

What does a downward slope on a distance-time graph indicate?

The object is returning towards the starting point.

What is the significance of the slope in a distance-time graph?

It tells you the speed of the object.

What does a horizontal line on a distance-time graph mean?

The object is stationary.

How can you determine the acceleration of a car that increases its velocity from 0 m/s to 10 m/s in 5 seconds?

By using the formula: acceleration = change in velocity / time taken = (10 m/s - 0 m/s) / 5 s = 2 m/s².

What is the effect of a steeper incline on a trolley's acceleration?

It results in greater acceleration.

What does it mean when an object has zero acceleration?

The object is moving at a constant velocity.

What is the acceleration of a trolley on a gentle incline compared to a steep incline?

A gentle incline results in less acceleration than a steep incline.

What is the significance of the acceleration due to gravity in free fall?

It affects all falling objects, causing them to accelerate towards the Earth.