Flashcards in Our Dynamic Universe Deck (24):
What is acceleration?
The rate of change of velocity
How is acceleration determined from a speed time graph?
The gradient of the line
What is Newton’s first law?
An object with balanced forces will move at a constant speed or remain at rest
What is Newton’s second law?
An unbalanced force will cause an object to accelerate in the direction of the unbalanced force
What is Newton’s third law?
If object A exerts a force on object B, object B will exert an equal but opposite force on object A
What happens to a falling object in terms of forces?
An object in free fall will initially accelerate because weight is greater than air resistance.
As air resistance increases, weight remains constant until the forces are balanced and the object moves at terminal velocity.
When a lift is decelerating upwards is weight or tension greater?
When a lift is decelerating downwards is tension or weight greater?
What equation is used when weight is acting down a slope?
What equation is used when weight is acting into a slope?
How is the newton defined?
The unbalanced force required to accelerate 1kg at 1ms^-2
What is energy?
The ability to do work
What is work done?
The amount of energy transformed into another form
What does the law of conservation of energy state?
Energy cannot be created or destroyed, it simply changes from one form to another
What is power?
The rate at which energy changes form
What is momentum measured in?
What is the principle of conservation of momentum?
For any interaction between two objects total momentum before is equal to the total momentum after
What is an elastic collision?
One in which kinetic energy and momentum are both conserved
What is an inelastic collision?
One in which only momentum is conserved
Why does projectile motion occur?
Objects experience constant horizontal velocity and constant vertical acceleration
How do satellites work?
They are projectiles and therefore are in free fall around a planet/Star
What does Newton’s law of gravitation state?
The gravitational attraction between two objects is directly proportional to the mass of each object and inversely proportional to the square of the distance apart
What are the two postulates of special relativity?
-When two observers are moving at constant speed relative to each other they will experience the same laws of physics
-the speed of light in a vacuum is constant and is the same for all observers