Flashcards in Motion And Forces Deck (27)
Define a scalar.
It has magnitude but not direction
Define a vector.
Has both magnitude and direction
Name 3 scalars.
Name 3 vectors.
Speed in a given direction
What is the main advantage of using light gates to measure time?
It eliminates human reaction time error
Define resultant force.
One force that replaces many forces
When two bodies interact, what can you say about the size and direction of the action and reaction force?
Equal and opposite
What will happen to an objects motion if the resultant force is not zero?
Stay at rest, or continue at a constant velocity
What will happen to an objects motion if the resultant force is zero?
Accelerate or decelerate
State Newton's First Law.
When a resultant force is zero a body is constant velocity or at rest. If the resultant force is not zero the body will accelerate
State two factors that will affect the acceleration of an object.
Size of resultant force
Mass of object
What is Newton's second Law?
Force = Mass x Acceleration
Describe the acceleration of a body free falling in a vacuum.
Constant acceleration (10m/s squared on Earth)
Describe the difference between mass and weight.
Weight is a force measured in Newtons. Mass is a measurement of the amount of matter, measured in kg. Weight changed dependant on the gravitational field strength.
Describe the velocity of an object moving in a circle.
The direction of an object moving in a circle is constantly changing therefore it's velocity is constantly changing
Why must there be a resultant force acting an object moving in a circle?
An object moving in a circle is constantly changing therefore it must be accelerating. For an object to accelerate it must have a force acting upon it
What is the name of the force acting on an object moving in a circle?
What is inertial mass?
It is a measure of how difficult it is to change velocity of an object. Also defined as ratio of force over acceleration
What is Newton's third law?
For every action, there is an equal and opposite reaction. In every interaction, there is a pair of forces acting on the two objects. The forces are the same magnitude but different directions
What two factors make up the overall stopping distance of a car?
Thinking distance plus braking distance
State three factors that will increase the braking distance of a car.
Poor condition of the road
State three factors that will increase the thinking distance of a car.
Momentum = Mass x Velocity
State Newton's second law in terms of momentum.
Force = change of momentum / time taken
State the conservation of momentum.
The momentum before the collision will be the same as the momentum after the collision