Newton's Laws Flashcards
What are the main points of newtons first law of motion?
- It predicts the behavior of objects for which all forces are balanced
-It states that if the forces acting on an object are balanced then the acceleration of the object will be 0m/s/s.
-Objects at equilibrium will not accelerate
- According to this law an object will only accelerate if there is a net or unbalanced force acting which will accelerate it - change its speed, direction or both.
What are the main point of the second law?
- Refer to the behaviour of objects for which all forces are not balanced.
- The acceleration of any object is directly dependent on the net force acting on an object and inversely upon the mass of the object.
What does Newton’s First Law state?
An object at rest will remain at rest and an object in uniform motion will remain in uniform motion unless acted upon by an external forse.
What does Newton’s Second Law of motion state?
The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. a =Fnet/m
The resultant force acting on an object is proportional to the rate of change of momentum p=mv of the object. Another way of putting this is that if a net, external force F affects an object for a time Δt, then the impulse of the force (FΔt) is proportional to the change in momentum.
What is the relationship between acceleration with force and mass
As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased. Fnet = m x a
If the force is double or tripled then acceleration will double or triple. If the mass is doubled or tripled then the acceleration will be one-half or one third etc
Suppose that a horse cart is accelerating at a rate of 2 m/s/s. If the net force is tripled and the mass is doubled, then what is the new acceleration of the sled?
Suppose that a horse cart is accelerating at a rate of 2 m/s^2. If the net force is tripled and the mass is halved, then what is the new acceleration of the sled?
3ms-2
12ms-2
What is the definition of 1 Newton?
The definition of the standard metric unit of force is stated by the above equation. One Newton is defined as the amount of force required to give a 1-kg mass an acceleration of 1 m/s/s.
What is momentum?
The product of mass and velocity
When a force acts on an object that is able to move or is moving there is a change in momentum.
How is momentum calculated?
Momentum (P) = mass (m) x velocity (v)
the unit of momentum is kgms-1
What is a moment and how is it calculated?
The tendency of an object to rotate around a pivot or xis.
Force x perpendicular distance from the pivot.
What insight does momentum give us?
how much force would be required to stop a moving object within a particular time frame.
A lorry has a mass of 7,500 kg. It travels south at a speed of 25 m/s. Calculate the momentum of the lorry.
187,500kgms-1
The momentum of the body is given by the equation below,
p(t) = 3t^2 + 4t + 5
Find the force acting on the body at t = 5.
34N
What are the main points of Newton’s third law.
-Whenever two or more objects interact with each other, they exert forces upon each other. These forces are called action and reaction forces.
-The size of the forces on the first object equals the size of the force on the second object.
-The direction of the force on the first object is opposite to the direction of the force on the second object.
-Forces always come in pairs - equal and opposite action-reaction force pairs.
What does Newton’s Third Law state?
Whenever two object interact with each other the force’s they exert on each other are equal in magnitude and opposite in direction.
For every reaction there is an equal and opposite reaction.
