The magnitude of the kinetic friction force, ƒk, on an object is. Where μk is called the kinetic friction coefficient and |FN| is the magnitude of the normal force of the surface on the sliding object. The kinetic friction coefficient is entirely determined by the materials of the sliding surfaces. hope it helps
Answer:
a) dh/dt = -44.56*10⁻⁴ cm/s
b) dr/dt = -17.82*10⁻⁴ cm/s
Explanation:
Given:
Q = dV/dt = -35 cm³/s
R = 1.00 m
H = 2.50 m
if h = 125 cm
a) dh/dt = ?
b) dr/dt = ?
We know that
V = π*r²*h/3
and
tan ∅ = H/R = 2.5m / 1m = 2.5 ⇒ h/r = 2.5
⇒ h = (5/2)*r
⇒ r = (2/5)*h
If we apply
Q = dV/dt = -35 = d(π*r²*h/3)*dt
⇒ d(r²*h)/dt = 3*35/π = 105/π ⇒ d(r²*h)/dt = -105/π
a) if r = (2/5)*h
⇒ d(r²*h)/dt = d(((2/5)*h)²*h)/dt = (4/25)*d(h³)/dt = -105/π
⇒ (4/25)(3*h²)(dh/dt) = -105/π
⇒ dh/dt = -875/(4π*h²)
b) if h = (5/2)*r
Q = dV/dt = -35 = d(π*r²*h/3)*dt
⇒ d(r²*h)/dt = d(r²*(5/2)*r)/dt = (5/2)*d(r³)/dt = -105/π
⇒ (5/2)*(3*r²)(dr/dt) = -105/π
⇒ dr/dt = -14/(π*r²)
Now, using h = 125 cm
dh/dt = -875/(4π*h²) = -875/(4π*(125)²)
⇒ dh/dt = -44.56*10⁻⁴ cm/s
then
h = 125 cm ⇒ r = (2/5)*h = (2/5)*(125 cm)
⇒ r = 50 cm
⇒ dr/dt = -14/(π*r²) = - 14/(π*(50)²)
⇒ dr/dt = -17.82*10⁻⁴ cm/s
Answer Part A: radiation
Part B: conduction
Part C: conduction
Part D: conduction
Part E: conduction
Part F: radiation
Part G::radiation
Part H : convection
Explanation:conduction is heat transfer through direct contact
Convection is through molecules or particles of water or air current
Radiation is heat transfer through empty space .
No, that doesn't work.
[work] divided by [force] = [distance] .
Power = (amount of work done) divided by (time to do the work) .
The distance of dodo is 150 cm.
<h3>What is focal length of lens?</h3>
The distance between a lens's center and its focal point is its focal length. A focal point is a location on the principal axis where, following refraction via the lens, light rays parallel to the principal axis either actually meet or appear to meet.
Given parameters:
the focal length of David's lens is: f = 50 cm.
magnification is: m = -0.50
We have to find: distance of dodo, that is, object's distance : u = ?
We know that:
u =f( 1/m -1)
⇒ u = 50(-1/0.50-1) = - 150 cm.
Hence, distance is 150 cm.
Learn more about focal length here:
brainly.com/question/16188698
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