Force and Momentum Flashcards
Newton’s First Law of Motion
An object remains at rest or in uniform motion unless acted on by a force.
Newton’s Second Law of Motion
The rate of change of momentum of an object is proportional to the resultant force on it. Or, the resultant force is proportional to the change of momentum per second.
Newton’s Third Law of Motion
When two objects interact, they exert equal and opposite forces on each other.
The momentum of an object is defined as mass multiplied by its velocity. What is the unit of momentum?
The unit of momentum is kg ms^-1. Momentum is also a vector quantity, it’s direction is the same as the direction of the object’s velocity.
According to Newton’s second law, the force is proportional to the change of momentum per second. Therefore, what is the equation for force?
F = (mv-mu)/t
This equation is the same as F = ma as (v-u)/t is the same as acceleration.
How would you calculate the change of momentum on a force-time graph?
Calculate the area under the line.
What are the two units of momentum?
Ns
or
kg ms^-1
What is the equation used if an object rebounds at an angle of theta ?
F = (-2mu*cos(theta))/t
This assumes that u=v where theta is from the perpendicular plane.
What are the two types of collisions?
Elastic and inelastic.
What is an elastic collision?
An elastic collision is one where is no loss of kinetic energy.
What is a totally inelastic collision?
A totally inelastic collision is where the colliding objects stick together afterwards.
What is a partially inelastic collision?
A partially inelastic collision is when the objects do not stick together after colliding but move apart with less momentum.
