Physics - Newtons laws Flashcards
What is the difference between mass and weight?
Mass - the amount of matter in an object. Measured in kilograms (kg).
Weight - the force of gravity on your mass. Measured in Newtons (N)
What’s the equation for weight?
Weight(N) = Mass (kg) x gravitational field strength (N/kg)
W=m x g
What is inertia?
Inertia is a resistance to a change in motion.
More mass means more inertia. A greater resultant force will be needed to change the motion of an object with high inertia.
What is newtons first law?
An object will remain at rest or at a constant velocity unless acted upon by an external force.
What is Newtons second law?
When the forces acting on an object do not balance, the resultant force will cause the object to accelerate in the direction of the resultant force.
What is the equation in relation to newtons second law? (Resultant force)
Resultant force (N) = Mass(kg) x acceleration (m/s2)
F=m x a
What is terminal velocity?
The maximum speed an object, reached when the forces moving the object are balanced by its frictional forces. It stops accelerating but continues to travel at a constant speed.
How do you interpret a velocity time graph?
A rising line mean acceleration. Weight force is greater than drag
A horizontal line means the speed is constant. The drag is equal to the weight, so there is no resultant force to cause acceleration.
How is air resistance/drag created?
Moving through the air causes collisions with air molecules. There is friction between the moving body and the particles, which causes some of the kinetic energy of the moving body to be converted into heat. Additionally, the air molecules bounce off the object gaining kinetic energy.
Why does drag increase with speed?
The faster an object moves, the greater the number of collisions with air molecules. This increases friction, and the air molecules bouncing off gain even more kinetic energy.
What is newtons third law?
Whenever two objects interact, the forces they exert on each other are equal and opposite.
In other words, if body A exerts a force on body B, B exerts an equal and opposite force on A.
