physics - forces and motion Flashcards
(33 cards)
What are typical values for the speed of walking, running, and cycling?
- Walking: 1.5 m/s
- Running: 3 m/s
- Cycling: 6 m/s
Typical speeds can vary based on individual fitness levels and conditions.
What is a typical value for the speed of sound in air?
330 m/s
This value can change with temperature and pressure.
What is non-uniform motion?
Motion in which the speed is not constant.
How do we calculate average speed for non-uniform motion?
Average speed = total distance / total time.
What is the difference between speed and velocity?
- Speed: scalar quantity, only has magnitude
- Velocity: vector quantity, has magnitude and direction.
What is the difference between distance and displacement?
- Distance: length of the total journey (scalar)
- Displacement: straight line distance between start and end points (vector).
How do you calculate average velocity?
Average velocity = displacement / time.
What is acceleration?
The rate at which an object’s velocity changes.
What is the unit of acceleration?
m/s² (metres per second squared).
How do you calculate acceleration?
Acceleration = change in velocity / time.
How can something be moving at a constant speed but changing velocity?
An object moving in a circular path can maintain constant speed while changing direction.
What does a distance-time graph tell us?
- Straight line: constant speed
- Gradient: speed
- Horizontal line: stationary
- Increasing gradient: accelerating
- Decreasing gradient: decelerating.
How do you determine the speed of an object undergoing uniform motion?
Find the gradient of the line in the period of interest.
How do you determine the speed of an object undergoing non-uniform motion at a particular point in time?
Draw a tangent to the curve and determine the gradient of the tangent.
What does a velocity-time graph tell us?
- Straight sloping line: constant acceleration
- Horizontal line: constant speed.
What happens if the acceleration is constant?
The relationship v² = u² + 2as can be used.
How do you determine distance travelled from a speed-time graph?
Distance can be obtained by determining the area under the speed-time graph.
What is Newton’s first law?
If no resultant force acts on an object, its motion will not change.
What is Newton’s second law?
The acceleration of an object is directly proportional to the resultant force and inversely proportional to the mass.
What is the formula for Newton’s second law?
F = ma.
What is inertial mass?
A measure of how difficult it is to change an object’s velocity.
How can Newton’s second law be verified experimentally?
By measuring acceleration while changing mass or force.
What happens to the forces and acceleration of a falling object?
The object accelerates at g = 9.8 m/s² until terminal velocity is reached.
What is stopping distance?
The total distance required to stop a moving vehicle.
