P10) Force And Motion Flashcards
What does Newton’s second law of motion say the acceleration of an object is?
1) proportional to resultant force on object.
2) inversely proportional to mass of object
How do you calculate the resultant force on an object from its acceleration and its mass?
Resultant force, F (newtons, N) = mass, m (kilograms, kg) * acceleration, a (metres per second, m/s**2).
What is the inertia of an object?
The tendency of object to stay at rest or to continue in uniform motion (e.g. moving at constant velocity).
What is the inertial mass of an object?
Measure of difficulty of changing object’s velocity.
What can inertial mass be defined as?
Force ÷ acceleration.
What us the mass of an object?
Force acting on it due to gravity.
What does the mass of an object depend on?
Quantity of matter in it.
What is mass measured in?
Kilograms, kg.
What is the weight of an object measured in?
Newtons, N.
What is the gravitational force on an 1kg object?
Gravitational field strength at place where object is.
What is gravitational field strength measured in?
Newtons per kilogram (N/kg).
What is the equation for calculating the force due to gravity which acts on it if we know the mass?
Weight, W (newtons, N) = mass, m (kilograms, kg) * gravitational field strength, g (newtons per kilogram, N/kg).
What is the terminal velocity of an object?
When object reaches constant velocity when frictional force on it is equal + opposite to its weight.
What is stopping distances in a driving test?
Shortest distance a vehicle can safely stop in, + is in 2 parts.
1) thinking distance.
2) braking distance.
What is thinking distance?
Distance travelled by vehicle in time takes driver to react (e.g. during drivers reaction time).
What is the braking distance?
Distance travelled by vehicle during time braking force acts.
What is the relationship between the speed, reaction time and thinking distance?
Thinking distance = speed * reaction time.
What is the equation for calculating the momentum of a moving object?
Momentum of moving object, p (kg m/s) = mass, m (kg) * velocity, v (m/s).
If an object is elastic does it go back to its original shape?
Yes.
If an object doesn’t return to its original shape after being deformed what is it said to have been?
Inelastically deformed.
What is Hooke’s law?
Extension of a spring directly proportional to force applied, as long as limit of proportionality not exceeded.
What is Hooke’s law written as an equation?
Force applied, F (newtons, N) = spring constant, k (newtons per metre, N/m) * extension, e (metres, m).
