4.3 Equations of Motion Flashcards
What is distance?
the total length between two points
What is speed?
the total distance travelled per unit of time
What is displacement?
the distance of an object from a fixed point in a specified direction
What is velocity
the rate of change of displacement of an object
What is acceleration
the rate o change of velocity of an object
What is the equation of velocity?
v = change in displacement/time
what is the equation of acceleration
a = change in velocity/time
What is instantaneous speed (or velocity)?
the speed of an object at any given point in time
How is acceleration shown on a displacement time graph?
a curved line
- it has a changing velocity
How is velocity shown on a displacement time graph?
gradient of a straight line
- may be at a tangent to the curve
What is the average speed?
the total distance/ time
How do you find average speed on a displacement time graph?
- divide the total displacement by the total time
gradient of the line
what are the 3 motion graphs?
displacement time graphs
velocity time graphs
acceleration time grahs
How can you find velocitythe on a displacement time graph?
the gradient
- positive slope represents motion in the positive direction
- negative slope represents motion in the positive direction
How do you find the acceleration on a dt graph?
curved line
What is the area under the curve of a dt graph?
nothing
What does a horizontal line represent on a dt graph?
a state of rest
What is the initial displacement of a dt graph?
the y intercept
How is the acceleration shown on a velocity time graph?
- the gradient of the slope
- a positive slope represents an increase in velocity in the positive direction
- a negative slope represents an increase in velocity in the negative direction
- a curved line represents non-uniform acceleration
How is constant velocity represented on a vt graph?
a horizontal line
How is displacement represented on a vt graph?
the area under the curve
What can be shown on an acceleration time graph?
- y intercept is initial acceleration
- horizontal line is constant acceleration
- area under the curve is the change in velocity
What is the acceleration due to gravity of a bouncing ball?
- always in the same direction in a uniform gravitational field such as earths surface
What is the velocity of a bouncing ball?
- because the ball is going up and down it changes direction
- thus the velocity of the ball will change from - to + dependent on the direction
In projectiles; what is the time of flight?
how long the projectile is In the air
in projectiles; what is the maximum height attained
the height w
at which the projectile is momentarily at rest
In projectiles; what is range?
the horizontal distance travelled by the projectile
What are the 3 possible scenarios for projectile motion
- vertical projection
- horizontal projection
- projection at an angel
What are drag forces
forces that oppose the motion of an object moving through a fluid
What are the properties of drag forces?
- always in the opposite direction to the direction of motion of the object
- never speed up an object or start them moving
- slow down an object or keeps them moving air a constant speed
- converts kinetic energy into heat and sound
What is lift?
an upwards force on an object moving through a fluid perpendicular to the flow
What is the relationship between drag forces and the speed of an object
as the speed increases the drag increases
What is air resistance?
an example of a drag force that objects experience when moving through the air
what is the relationship with air resistance and th speed of an object?
air resistance increase with the speed of the object
What factors effect the maximum speed of the object, other than air resistance?
- cross sectional area
- shape
- altitude
- temprature
- humidity
how does air resistance effect projectiles?
- it decreases the horizontal component of the velocity of a projectile
- thus the range and max height is decreased compared to no air resistance
what does it mean if air resistance is negligible?
- the air resistance is so small it does not make a difference to the motion of the object.
- thus you do not take any drag forces into account during calculations
What is terminal velocity?
the maximum velocity that the object can have
- when drag forces are equal to the gravitational pull on the body and the body will no longer accelerate and fall at a constant velocity
What is the relationship between acceleration and drag forces?
the drag forces increase as the body acelerates
- increasing velocity means drag forces will increase
