Laws of Motion Test
Terms
copy deck
 What is a change in velocity for some time interval? Formula for it?
 acceleration, change in velocity divided by time
 What is any push or pull on an object?
 a force
 What do forces cause?
 acceleration, go slower or faster, change direction
 Force is measured in what unit?
 Newtons
 What are the two types of forces?
 Contact and field
 Which type of force is where objects collide causing acceleration?
 contact force
 Which type of force operates over an open space?
 field force
 Name the four types of field forces.
 gravity, electromagnetic, weak nuclear, strong nuclear
 What is the difference between weak and strong nuclear forces?
 Stong happens inside the nucleus and is the strongest known force. Weak happens outside the nucleus causing radioactivity.
 What is the theory attempting to prove all four field forces are the same thing?
 Grand Unification Theory
 With a field force the ________ you get the stronger the force becomes.
 closer
 What is Newton's first law of motion?
 Objects remain at constant velocity unless acted upon by an outside force.
 What is Newton's 2nd law of motion?
 Acceleration of an object is inversely proportional to an object's mass and directly proportional to the applied force.
 What is the formula used to find force or net force?
 f=(m)(a); force equals mass times acceleration
 What is Newton's 3rd law?
 For every action, there is an equal and opposite reaction.
 What is the sum of all forces acting on an object?
 the net force
 What is the pull of gravity on an object's mass?
 weight
 What is the difference between mass and weight?
 Weight is a force and vector measured in Newtons. Mass is a fundamental quantity (scalar) measured in kilograms.
 A normal force is ________ to the surface an object is resting on.
 perpendicular
 What force opposes motion?
 friction
 What are the two types of friction? What is the difference between the two?
 Static opposes the start of motion. Kinetic opposes motion in progress.
 What is the formula for the coefficient of static friction?

ìs=Fs/Fn
(coefficient equals the force of static friction divided by the normal force)  What is the formula for finding the coefficient of kinetic friction?

ìk=Fk/Fn
(The coefficient equals the force of kinetic friction divided by the normal force)  What are the three types of kinetic friction? Describe each briefly.

1)sliding surface to surface motion with no rotation
2)rolling one or more objects are rotating
3) fluid movement in a gas or liquid  Which type of kinetic friciton has the least friction?
 Fluid
 On a ramp, what force is at an angle?
 The force of gravity (weight)
 On a ramp, how does one find the angle to calculate the components of the force of gravity?
 Subtract the given angle from 90 degrees.
 Explain the relationship between mass and weight.
 They are directly related. Weight is the mass of an object times the acceleration rate of gravity.
 An object is at rest on a tabletop. If the tabletop is tilted slightly, does the normal force decrease or increase? What about the force of static friction? Explain.
 Both decrease. They are directly related.
 Why does pushing downward on a book as you push it across a table increase the force of friction between the table and the book?
 You increase the normal force which is directly related with friction.
 A sky diver falls through air. As the speed of the diver increases, what happens to his acceleration?
 Stays the same. Gravity is acting the same.
 What formula do you use when you have no acceleration?
 Ã„x=1/2(vi+vf)t
 What formula do you use when you have no final velocity?
 x=vit+1/2at2
 What formula do you use when you have no displacement?
 vf=vi+at
 What formula do you use when you have no time?
 vfÂ©Ã¼=viÂ©Ã¼+2aÂ¥Ã„x