Distance, Speed and Acceleration Flashcards
What is a vector quantity - definition?
a vector is a quantity that has both magnitude and direction.
what is a scalar quantity - definition?
a scalar is a quantity that has only magnitude.
Is speed a scalar or vector quantity?
Scalar
Is acceleration a scalar or vector quantity?
Vector
Is velocity a scalar or vector quantity?
Vector
What is speed?
The distance travelled in unit time.
What is velocity?
The displacement per unit time in a specified direction.
What is acceleration?
The rate of change of velocity per unit time.
what are the units for speed
m/s
what are the units for distance
m
what are the units for time
s
what are the units for acceleration
m/s2
metres per second squared
what are the units for velocity
m/s in direction (e.g. east)
What is reaction time (in driving)?
The time it takes for a driver to react to a stimuli and start applying the brakes.
What is thinking distance?
The distance a vehicle travels during the time that it takes for the driver to react and apply the brakes.
What is braking distance?
The distance a vehicle travels under the braking force, after the brakes are applied, until it comes to a complete stop.
What is overall stopping distance?
The thinking distance plus the braking distance.
What factors affect thinking distance? (5)
- speed
- alcohol/drugs
- tiredness
- visibility
- distractions (e.g. mobile phones)
What factors affect braking distance? (5)
- speed
- condition of tires
- weather (icy or wet road)
- mass of the car
- worn/new brakes
What are the purpose of speed limits in urban areas
To reduce stopping distance to reduce risk of collisions, and to reduce impact
What are the purposes of seat belts (2)
The protect people in the event of a collision by reducing the force experienced by their bodies. According to Newtons’ first law they would continue to move at the constant speed of the car unless acted upon by a force.
How does increase in speed affect stopping distance?
It increases it
