P10 - Force and Motion Flashcards
What is braking distance?
the distance travelled by a vehicle during the time it takes for its brakes to act
What is conservation of momentum?
in a closed system, the total momentum before an event is equal to the total momentum after the event.
Momentum is conserved in any collision or explosion, provided no external forces act on the objects that collide or explode
What is directly proportional?
a graph will show this if the line of best fit is a straight line through the origin
What is an elastic material?
a material is elastic if it is able to regain its shape after it has been squashed or stretched
What is extension?
the increase in length of a spring (or a strip of material) from its original length
What is gravitational field strength, g?
the force of gravity on an object of mass 1 kg (in newtons per kilogram, N/kg). It is also the acceleration of free fall
What is inertia?
the tendency of an object to stay at rest or to continue in uniform motion
What is limit of proportionality?
the limit for Hooke’s law applied to the extension of a stretched spring
What is mass?
the quantity of matter in an object / a measure of the difficulty of changing the motion of an object (in kilograms, kg)
What is the equation for momentum?
mass (in kg) x velocity (in m/s)
What is Newton’s second law of motion?
the acceleration of an object is proportional to the resultant force on the object, and inversely proportional to the mass of the object
What is stopping distance?
the distance travelled by the vehicle in the time it takes for the driver to think and brake
What is terminal velocity?
the velocity reached by an object when the drag force on it is equal and opposite to the force making it move
What is thinking distance?
the distance travelled by the vehicle in the time it takes the driver to react
What is weight?
the force of gravity on an object (in newtons, N)
What is acceleration?
the rate at which an object changes its velocity. It is measured in m/s²
What is a force?
A push or a pull that acts upon an object
What is inertial mass?
A measure of difficulty in changing an objects velocity
What is terminal velocity?
The maximum velocity of a free falling object, when the air resistance is equal to its weight
What is the stopping distance?
thinking distance + braking distance
What is the breaking distance?
The distance taken to stop once the breaks are applied
What is the thinking distance?
The distance travelled in between the driver realising he needs to break and actually breaking
What is momentum?
Mass x Velocity
What is the gravitational field strength on earth?
9.81 m/s²
What is newtons first law of motion?
An object at rest tends to stay at rest and an object in motion tends to stay in motion unless acted upon by an external force
What is newtons second law of motion?
Force = Mass x Acceleration
What is newtons third law of motion?
For every action there is an equal and opposite reaction
Which of newtons laws refer to inertia?
Newtons first law of motion
What quantity determines the magnitude of a body’s inertia?
mass
What are the conditions needed for a body to be stationary?
The resultant force on the object must be 0 and it must already be stationary
What are the conditions needed for a body to be moving at a constant speed?
The resultant force on the object must be 0 and it already be in motion
What are the conditions needed for a body to be moving at a constant acceleration?
The resultant force on the object must be in the direction it is travelling and it must already be in motion.
What is the resultant force on an object?
The net force acting upon an object. The resultant force has the same effect as all the forces acting upon an object combined