Forces Definitions Flashcards
Acceleration
The rate of change of velocity
Average speed
Distance over time for the entire region of interest
Braking distance
The distance travelled between the brakes being applied and the vehicle coming to a stop. It is affected by the vehicle and road conditions.
Displacement
The direct distance between an objects starting and ending positions. It is a vector quantity and so has both magnitude and direction.
Displacement-time graphs
Plots showing how displacement changes over a period of time. The gradient gives velocity. Curves lines represent acceleration.
Free-fall
And object is said to be in free fall when the only force acting on it is the gravity
Instantaneous speed
The exact speed of an object at a specific given point
Projectile motion
The motion of an object that is fired from a point and then upon which only gravity acts. When solving projectile motion problems, it is useful to split the motion into horizontal and vertical components
Reaction time
The time taken to process a stimulus and trigger a response to it. It is affected by alcohol, drugs, tiredness etc.
Stopping distance
The sum of thinking distance and taking distance for a driven vehicle
Thinking distance
The distance travelled in the time it takes for the driver to react. It is affected by alcohol, drugs, tiredness etc
Velocity - time graphs
Plots showing how velocity changes over a period of time. The gradient gives acceleration!. Curved lines represent changing acceleration.
Velocity
The rate of change of displacement. It is a vector quantity so has both magnitude and direction
Archimedes’ principle
The upwards force acting on an object submerged in a fluid, is equal to the weight of the displaced fluid
Couple
Two equal and opposite parallel forces that act on an object through different lines of action. It has the effect of causing a rotation without translation.
