revision topic 2 Flashcards
what is velocity?
speed in a given direction
how can two objects have the same speed but different velocity?
by moving at the same speed but not in one direction
what is displacement?
distance in a certain direction
what is a scalar?
a physical quantity that only has a magnitude
what is a vector?
a physical quantity that has both magnitude and direction
what is acceleration?
the change of velocity per second
what is deceleration?
negative acceleration
what does the area under the velocity-time graph represent?
the distance traveled by object
what is Newton’s second law?
acceleration of an object is:
directly proportional to the resultant force of the object
inversely proportional to the mass of the object
hence:
resultant force = mass x acceleration
the breaking force needed to stop a vehicle at a certain distance depends on?
- the speed of the vehicle when breaks are first applied
2. the mass of the vehicle
what is thinking distance?
the distance traveled by a vehicle in the time it takes the driver to react.
what is the braking distance?
the distance traveled by a vehicle during the time the breaks are first applied
what is stopping distance?
the shortest distance a vehicle can safely stop in
note: stopping distance = thinking distance + braking distance
what affects stopping distance
- being tired
- being under the effect of drug/alcohol
- going in a really high speed
- bad road conditions
- poorly maintained vehicle
explain streamlining
you can streamline a car to lower the drag force on it to reach the highest possible speed making a vehicle more efficient
