What are long range forces?
Those are forces that act on an object without physical contact. This includes gravity and magnetism.
What is the net force of an object?
It is the sum of all forces.
What is the definition of normal force?
It is the force of an object pushing back when force has already been applied to it.
What is kinetic friction?
It is friction that appears as an object slides against a surface.
What is static friction?
It is friction that keeps an objects stuck on a surface.
What is drag?
It is the resistive force of fluid particles
What is thrust?
It is the force that jets give off as it expels particles at high speed.
On a graph, how do Force and acceleration relate?
They are linear.
What is the equation that relates a constant, Force, and Acceleration?
a =cF
What is the equation that involves acceleration, a constant, and mass?
a = c/m, they are inversely proportional
What is the scientific definition of a Newton?
A newton is a force that causes a 1 kg mass to accelerate 1 m/s^2
What is the definition of inertia?
It is the tendency of an object to resist a change in velocity.
Two rubber bands stretched to the standard length cause an object to accelerate at 2 m/s^2. Suppose another object with twice the mass if pulled by four rubber bands stretched to the standard length. The acceleration of this second object is?
2 m/s^2
What causes an object to change its velocity?
A force is what causes an object to change its velocity.
How do you find an inertial reference frame? What does it determine?
An inertial reference frame is a reference frame in which Newton's laws are valid. To determine if it is an inertial reference frame Acceleration = 0 only if Force = 0. Accelerating reference frames are not inertial reference frames.
What is newtons second law?
F=m*a
What is newtons first law?
An object in motion stays in motion if and only if the net force on an object is zero.
If an object has an initial force does it have an initial velocity?
It can, but it doesn't have to.
Suppose you press your physics book against a wall hard enough to keep it from moving. In what direction does the friction force on the book point?
Up
What is the best way to determine if your frame of reference is a inertial reference frame?
If the frame you are looking at is not accelerating.
An object cannot remain at rest unless what aspect of force holds true?
The net force acting on it is zero.
If a block is moving to the left at a constant velocity, what can one conclude about the forces on it?
The net force applied to the block is zero.
A block of mass 2kg is acted upon by two forces: 3N (directed to the left) and 4N (directed to the right). What can you say about the block's motion?
It could be moving to the left, moving to the right, or be instantaneously at rest. The acceleration of an object tells you nothing about its velocity--the direction and speed at which it is moving. In this case, the net force on (and therefore the acceleration of) the block is to the right, but the block could be moving left, right, or in any other direction.
A massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. The block must be __________. Hint: what is its acceleration.
moving with a constant nonzero acceleration
How do you calculate the exact force of gravity on another object?
F = (GMm)/R^2, G = 6.67*10^-11
What is the equation for the gravity of a planet?
g = GM/R^2, G = 6.67*10^-11
Why are we missing "0.03 units" of acceleration for earth's gravity?
This is caused from the rotation of the earth.
Four balls are thrown up in the air. #1 is 200 g and is going 5 m/s. #2 is 300 g and is going 4 m/s. #3 is 300 g and is going 3 m/s. #4 is 400 g and is going 3 m/s. Rank in order the forces acting on them after they have been thrown.
#4 >#2 and #3 > #1. It all has to do with mass times gravity. They are all moving at a constant speed.
What force vector does a scale measure?
The normal force.
A hand presses down on the book on a table. Is the normal force of the table on the book larger than, smaller than, or equal to mg? Explain.
Larger than mg. This is because g is constant, but as the force of the hand increases, the normal force also increases.
What is the equation for friction?
Mew times normal force
Between static and kinetic friction, which one is stronger?
Static
When two objects are in contact with no relative motion, which of the following statements about the frictional force between them, is true?The frictional force is always equal to μsn.The frictional force is always less than μsn.The frictional force is determined by other forces on the objects so it can be either equal to or less than μsn.
The frictional force is determined by other forces on the objects so it can be either equal to or less than μsn.
What is the equation for drag?
D = 1/2CpAv^2
What is the equation for terminal speed?
v = sqrt(2mg/CpA)
When a board with a box on it is slowly tilted to larger and larger angle, common experience shows that the box will at some point "break loose" and start to accelerate down the board.The box begins to slide once the component of gravity acting parallel to the board Fg just begins to exceeds the maximum force of static friction. Which of the following is the most general explanation for why the box accelerates down the board?
The force of kinetic friction is smaller than that of maximum static friction, but Fg remains the same.