P10: Forces & Motion Flashcards
What does Newton’s Second Law state?
A resultant force will cause an object to accelerate (the acceleration of an object is proportional to the resultant force acting on an object, and inversely proportional to the mass)
What is the equation for a resultant force?
F = ma
What are the typical reaction times?
0.2s - 0.9s
What factors of the driver can affect reaction time?
Tiredness, drugs and alcohol
What factors can affect braking distance?
Wet or icy roads and poor condition of brakes or tyres
What happens when a force is applied to brakes?
Work done by friction between the brakes and the wheel reduces the kinetic energy of the vehicle and the temperature of the brakes increases
What is the equation for momentum?
Momentum = mass x velocity
What does the conservation of momentum state?
The total momentum before an event = the total momentum after an event
What is the equation for change in momentum?
Change in momentum = Force x change in time
What is the relationship between the extension of a string and the force applied?
They are directly proportional
What is the equation that includes extension and force?
Force = spring constant x extension
What does the size of air resistance depend on?
Surface area and velocity
When is terminal velocity reached?
When the resultant force is zero/the weight has the same magnitude as the air resistance
What does Newton’s First Law state?
A resultant force is required to change the motion of an object
What does Newton’s Third Law state?
When two objects interact, the forces they exert on each other are equal and opposite
