Newton's Law Flashcards
(41 cards)
What is Newton’s first law of motion?
A body will remain in its state of rest or motion at constant velocity unless a non-zero resultant/net force acts on it.
What are the two parts of Newton’s first law of motion?
An object in motion will continue in motion with the same velocity unless acted on by a net force.
What happens to an object at rest if no net force is applied to it?
It remains at rest.
Provide an example of an object at rest.
A box on a surface will not move if no force is applied to it because the forces are balanced.
What is the weight force and how is it calculated?
Weight force is the force of gravity on an object, calculated as ( W = m imes g ), where ( m ) is mass in kilograms and ( g ) is gravitational acceleration (9.8 m/s²).
Calculate the weight force of a 10 kg box on Earth.
( W = 10, ext{kg} imes 9.8, ext{m/s}^2 = 98, ext{Newtons} ).
What is the normal force?
The normal force, N, is the force or the component of a force which a surface exerts on an object in contact with it, and which is perpendicular to the surface.
How does the normal force act on a box at rest on a horizontal surface?
It balances the weight force, so for the 10 kg box, the normal force is also 98 Newtons.
What is the net force on a box at rest with balanced forces?
The net force is zero.
How does the normal force act on inclined planes compared to horizontal planes?
The normal force always acts perpendicular to the surface, regardless of whether the plane is horizontal or inclined.
What is inertia?
Inertia is the resistance of an object to any change in its state of motion. The mass of an object is a quantitative measure of its inertia.
How is inertia quantitatively measured?
By the mass of the object.
Why does a ball rolling on a carpet stop quickly?
Because friction opposes motion and acts as a net force, causing the ball to stop.
Why does a puck slide longer on ice than a ball on carpet?
Because there is less friction on the ice, allowing it to continue moving longer.
What forces slow down an object moving on Earth, even on ice?
Friction and air resistance.
Why can Earth revolve around the Sun for billions of years without slowing down?
Because in outer space, there is virtually no friction or air resistance to slow it down.
What is the net force acting on an object moving with constant velocity?
Zero.
What happens if the net force acting on an object is not zero?
The object experiences acceleration.
How is acceleration defined?
Acceleration is the change in velocity over time, ( a = rac{V_f - V_i}{Delta t} ), where ( V_f ) is final velocity, ( V_i ) is initial velocity, and ( Delta t ) is the change in time.
What is acceleration when velocity is constant?
Zero, because the final and initial velocities are the same.
State Newton’s second law of motion.
When a resultant/net force acts on an object, the object will accelerate in the direction of the force at an acceleration directly proportional to the force and inversely proportional to the mass of the object.
What is the formula expressing Newton’s second law?
( F = ma ), where ( F ) is net force, ( m ) is mass, and ( a ) is acceleration.
If acceleration is constant and mass increases, what happens to the net force?
The net force increases because it is directly proportional to the mass.
If mass is constant and acceleration increases, what happens to the net force?
The net force increases because it is directly proportional to acceleration.
