Dynamics Flashcards
Definitions from the N5 Dynamics sub-unit
What is meant by Average Speed?
The speed calculated over the entire distance and time of the motion. eg 40 miles in 2 hours is 20 mph
What is meant by Instantaneous Speed?
The speed at a specific point. Calculated
over a very short distance and time. eg 5cm
in 0.04s is 1.25 m/s
What is meant by Acceleration?
The change in velocity of an object in 1 second.
What is meant by “Positive acceleration”?
Velocity increasing
What is meant by “Negative acceleration”?
Velocity decreasing
How do you find the distance travelled from a v-t graph?
Calculate the area under the graph.
What is meant by a Scalar?
Magnitude (size) only
What is meant by a Vector?
Magnitude and a direction
What is meant by “Distance”?
The length of the route taken (magnitude only)
What is meant by “Displacement”?
The straight line length from start to end of a motion (magnitude & direction).
What is meant by “Direction by compass point”?
An angle from a compass point with a direction.
eg ‘43 degrees West of North’.
What is meant by “Direction by Bearing”?
A three figure angle clockwise from North. eg ‘bearing of 317’.
How do you calculate the speed of an object?
Scalar : speed = distance / time
How do you calculate the magnitude of the velocity of an object?
Vector : velocity = displacement / time
What 3 effects can a Force have?
- Change the shape of an object
- Change the speed of an object
- Change the direction of motion of an object
What is Newton’s First Law?
An object will remain at rest or travel in a
straight line with a constant speed, unless
an unbalanced force acts upon it.
What is Newton’s Second Law?
An unbalanced Force acting on an object
will cause the object to Accelerate. The size
of that acceleration will depend on the size
of the Force and the Mass of the object.
What is Newton’s Third Law?
If object A applies a Force on object B, then
object B applies and equal but opposite Force on A.
What is meant by “Terminal velocity”?
The maximum velocity of a falling object.
It occurs when the air resistance is equal in
size but opposite in direction to the weight of the object.
What is meant by the “Mass” of an object?
The amount of matter within an object.
The value does not change with position
What is meant by the “Weight” of an object?
The force due to gravity on a mass.
The value does change with position.
Describe the Horizontal motion of a Projectile.
Constant horizontal velocity
Describe the Vertical motion of a projectile.
Constant vertical acceleration
