Exam 2 Flashcards
What is the equation for centripetal (radial) acceleration?
a(R) = v^2/r
The direction of the force needed to keep an object revolving in a circle is pointed
toward the center of the circle
What is the equation for the magnitude of the gravitational force
F(G) = G(m1m2/r^2)
m1 and m2: the masses of the two particles
r: distance between them
G: 6.67 x 10^-11 N*m^2/kg^2
What is the equation for the period (T) of an object revolving around a circle?
T = 1/f
f: frequency
What is the equation for the net force in the radial direction (circular motion) that acts on an object?
∑F(r) = ma(R) = m(v^2/r)
T or F? There is no outward force on a revolving object
T
The gravitational force F(grav) or F(G) exerted by the Earth on any object decreases with the ____ from the Earth’s center
square of its distance r
What is the equation for the acceleration of gravity at the Earth’s surface?
g = G(m(E)/r(E)^2)
What is the mass of Earth (m(E))?
m(E) = 5.98 x 10^24 kg
What is Kepner’s first law?
The path of each planet around the Sun is an ellipse with the Sun at one focus
What is Kepner’s second law?
Each planet moves so that an imaginary line drawn from the Sun to the planet sweeps out equal areas in equal periods of time
What is Kepner’s third law?
The ratio of the squares of the periods T of any two planets revolving around the Sun is equal to the ratio of the cubes of their mean distances from the Sun
(T1/T2)^2 = (s1/s2)^3
T1 and T2: periods (time needed for one rev around the Sun)
s1 and s2: mean distances from the Sun
Equation for velocity of circular motion?
v = 2πr/ T
Newton’s laws are causal laws. This means that
one occurrence can causes another
Energy and momentum are
conserved
Work and energy have no ___ associated with them
direction
What does work describe?
what is accomplished when a force acts on an object, and the object moves through a distance
What is the equation for work?
W = F||d
What is another equation for work?
W = Fd cosθ
What is the unit for work?
joule
1 J = 1 N * m
You need both a ___ and a ___ to do work
force; displacement
When a particular force is perpendicular to the displacement,
no work is done by that force
What is the equation for translational kinetic energy?
KE = 1/2mv^2
What is the equation for net work?
W(net) = 1/2mv2^2 - 1/2mv1^2 W(net) = ΔKE