Module 1 Flashcards
What is the prefix for 10^12?
tera (T)
What is the prefix for 10^9?
giga (G)
What is the prefix for 10^6?
mega(M)
What is the prefix for 10^3?
kilo (k)
What is the prefix for 10^2?
hecto (h)
What is the prefix for 10^1?
deka (da)
What is the prefix for 10^-1?
deci (d)
What is the prefix for 10^-2?
centi (c)
What is the prefix for 10^-3?
milli (m)
What is the prefix for 10^-6?
micro(m)
What is the prefix for 10^-12?
pico (p)
What is the prefix for 10^-15?
femto (f)
What are the 7 fundamental units?
meter (m) second (s) kilogram (kg) ampere (A) kelvin (K) mole (mol) candela (cd)
What is mechanics?
the study of the motion of objects and the related concepts of force and energy
What are the two parts of mechanics?
kinematics and dynamics
what is kinematics?
description of how objects move
what is dynamics?
deals with force and why objects move
What is speed?
how far an object travels in a given time interval, regardless of direction
What is average speed?
the total distance travelled along its path divided by the time it takes to travel this distance
What is one difference between speed and velocity?
speed is a positive number while velocity is used to signify both the magnitude (numerical value) of how fast an object is moving and also the direction in which it is moving.
What is velocity
used to signify both the magnitude (numerical value) of how fast an object is moving and also the direction in which it is moving. Velocity is a vector quantity.
What is average velocity?
defined in terms of displacement rather than total distance travelled
average velocity =
(final position - initial position) / time elapsed
average speed =
distance traveled / time elasped
What is instantaneous velocity?
average velocity over an infinitesimally short time interval
What is acceleration?
how rapidly the velocity of an object is changing
average acceleration =
change in velocity/time elapsed
When is instantaneous and average acceleration equal?
when the magnitude of the acceleration is constant
what equation for constant acceleration, finds the velocity of an object after any elapsed time when given objects constant acceleration?
v = at + v₀
which equation for constant acceleration, finds the position of x after a time when it undergeos constant acceleration?
x = x₀ + v₀t + 1/2at²
which equation for constant acceleration, will show that average velocity is midway between initial and final velocities?
average velocity = (v₀ + v) / 2
which equation for constant acceleration, finding velocity when time is unknown
v²= v₀² + 2a(x-x₀)
What is galileo’s understanding of the motion of falling objects?
at a given location on earth and in the absence of air resistance all objects fall with the same constant acceleration due to gravity
Is it right that “acceleration and velocity are always in the same direction”?
Wrong, Velocity and acceleration are not necessarily in the same direction. When the ball in Fig. 2–23 is moving upward, its velocity is positive (upward), whereas the acceleration is negative (down- ward).
Is it right “that an object thrown upward has zero acceleration at the highest point”?
Wrong, At the highest point , the ball has zero velocity for an instant. Acceleration is not zero at this point. The velocity near the top of the arc points upward, then becomes zero for an instant (zero time) at the highest point, and then points downward. Gravity does not stop acting, so a = –g = –9.80 m/s2 even there. Thinking that a = 0 at point B would lead to the conclusion that upon reaching point B, the ball would stay there: if the acceleration ( = rate of change of velocity) were zero, the velocity would stay zero at the highest point, and the ball would stay up there without falling. Remember: the acceleration of gravity always points down toward the Earth, even when the object is moving up.

What are the four equations for constant acceleration?
v = at + v₀
x = x₀ + v₀t + 1/2at²
average velocity = (v₀ + v) / 2
v²= v₀² + 2a(x-x₀)
what is projectile motion
objects projected outward near the Earth’s surface
What are scalar quantities?
no direction associated with them
what are vector quantities?
has direction as well has magnitude
When multiplying the vector by a positive scalar c what happens?
changes the magnitude of the vector by a factor c but doesn’t alter the direction
When multiplying the vector by a negative scalar c what happens?
the magnitude of the produce cV is changed by the factor |c| (where |c| means the magnitude of c) but the direction is precisely opposite to that of V
What is force?
any kind of a push or a pull on an object
What are the two types of force?
contact force and force of gravity
What is contact force?
forces exerted when one object comes in contact with another object
What is the force of gravity?
why objects fall (non-contact force)
What is Newton’s first law of motion?
every object continues in its state of rest, or of uniform velocity in a straight line, as long as no net force acts on it
What is inertia?
tendency of an object to maintain its state of rest or of uniform velocity in a straight line
What is mass?
the measure of inertia of an object
The more mass an object has…
the greater the forced needed to give it a particular acceleration
What is Newton’s second law of motion?
that if no net force is acting on an object at rest, the objet remains at rest; or if the object is moving, it continues moving with constant speed in a straight line.
What happens if net force is exerted on an object? (2)
it can increase or if the net force is in an opposite direction to the motion it will reduce the velocity.
What does sideways net force do to an object?
If the net force acts sideways on a moving object, the direction of the object’s velocity changes, the change in the direction of velocity is acceleration.
Therefore net force causes acceleration
the greater the mass (second law)
the less the acceleration for the same net force
what is the relationship between acceleration, an object and mass?
the acceleration of an object is directly proportional to the net force acting on it, and is inversely proportional to the object’s mass. The direction of the acceleration is in the direction of the net force acting on the object.
What is the equation for newton’s second law of motion?
a= ƩF / m
What are the kinematic equations for constant acceleration in two dimensions (x component (horizontal)) (3)
Vx = Vx₀ + (ax)t
x = x₀ + (Vx₀)t +1/2(ax)t²
Vx²=Vx₀² + 2ax(x-x₀)
What are the kinematic equations for constant acceleration in two dimensions (y component (vertical) (3)
Vy = Vy₀ + (ay)t
y = y₀ + (Vy₀)t +1/2(ay)t²
Vy²=Vy₀² + 2ay(y-y₀)
What are the kinematic equations for projectile motion (horizontal motion)? (2)
ax=0, Vx= constant
Vx = Vx₀
x = x₀ + Vx₀t
What are the kinematic equations for projectile motion (vertical motion)? (3)
ay= -g = constant Vy = Vy₀ - gt y = y₀ + Vy₀t - 1/2gt² Vy² = Vy₀² - 2g(y-y₀)
What is newton’s third law of motion?
Whenever one object exerts a force on a second object, the second object exerts an equal force in the opposite direction on the first.
What happens when a cord has negligible mass, when pulled?
the force exerted at one end is transmitted undiminished to each adjacent piece of cord along the entire length to the other end. As ƩF = ma = 0, as the the cord’s mass is zero no matter what a is. Forces must add up to zero
What happens to friction when an object slides along a rough surface?
the force of kinetic friction acts opposite to the direction of the object’s velocity.
What is work?
describe what is accomplished when a force acts on an object through a certain distance
What is the work energy principle?
Net work done on an object is equal to change in its KE
In general, the change in potential energy associated with a particular force is equal to….
the negative of the work done by that force when the object is moved from one point to a second point.
What happens to the total mechanical energy of a system?
it stays constant
