SP2 Flashcards
(33 cards)
What is the resultant force of an object?
The total force that results from two or more forces acting upon a single object.
How can we figure out if the forces on an object are balanced or not?
If the resultant force is zero, the object is balanced. Otherwise, it is unbalanced.
What is Newton’s First Law of motion?
A moving object will continue to move at the same speed and direction unless an external force acts on it.
A stationary object will remain at rest unless an external force acts on it.
What is the centripetal force?
A force that causes objects to follow a circular path and acts towards the centre of the circle.
What is mass?
The quantity of matter there is in an object which only changes if the object itself changes.
What is weight?
A measure of the pull of gravity on an object and depends on the strength of gravity.
How do we measure weight?
Using a force meter.
How do we calculate the weight of an object?
Weight (N) = mass (kg) × gravitational field strength (N/kg)
W = m × g
How is air resistance related to speed?
Air resistance increases as speed increases.
What is Newton’s Second Law of motion?
It describes the factors that affect the acceleration of an object.
The acceleration in the direction of a resultant force depends on:
- The size of the force (for the same mass, the bigger the force the bigger the acceleration)
- The mass of the object (for the same force, the more massive the object the smaller the acceleration)
How do we calculate the force acting on an object?
Force (N) = mass (kg) × acceleration (m/s²)
F = m × a
What is Newton’s Third Law of motion?
It is about the forces on two different objects when they interact with each other.
For every action, there is an equal and opposite reaction.
What are action-reaction forces?
A pair of forces acting on the two interactive objects.
What is the difference between balanced forces and action-reaction forces?
Action-reaction forces act on different objects while balanced forces act on the same object.
What is momentum?
A measure of the tendency of an object to keep moving or of how hard it is to stop moving.
How do we calculate momentum?
Momentum (kg m/s) = mass (kg) × velocity (m/s)
p = m × v
How do we calculate the force related to momentum and time?
change in momentum / mass × change in velocity
Force = ____________________________________________________
time
OR
mv-mu
F = _________
t
What is the conservation of momentum?
When moving objects collide, the total momentum of both objects is the same before the collision as it is after the collision, as long as there are no external forces acting.
What is the thinking distance?
The distance travelled by a vehicle while the driver reacts.
What is the braking distance?
The distance travelled by a vehicle while the brakes are working to bring it to a halt.
What is the stopping distance?
The total distance in which a car stops.
How do we calculate the stopping distance?
Stopping distance = thinking distance + braking distance
What is reaction time?
The time between a person detecting a stimulus and their response.
How can we measure reaction time?
Using computers or electric circuits.
