Answer:
b. Friction decreased when he went from pavement to ice and then increased two more times.
Explanation:
Frictional force depends on the normal force of the surface and a friction coefficient.
Since we're talking about the same car, the value of 
will remain constant whereas μ will represent the change in the frictional coefficient of the surface. Now we consider the different surfaces, cars will slide in an icy road which means that the frictional coefficient is smaller than the pavement.
After Joshua returns to the pavement road, the resulting frictional force increases and will do so one more time when he reaches the gravel road. Gravel roads have greater frictional coefficients than pavement roads which means the frictional force will increase a second time.
Answer:
Explanation:
The formula for gravitational potential energy is
Ep = m · g · h Assuming that the acceleration is g = 10m/s²
Ep = 45.4 · 10 · 21.9 = 9,942.6 J
God is with you!!!
Answer: thermal
Explanation:
Moving particles transfer thermal energy through a fluid by forming convection currents.
Answer:
solution:
dT/dx =T2-T1/L
&
q_x = -k*(dT/dx)
<u>Case (1) </u>
dT/dx= (-20-50)/0.35==> -280 K/m
q_x =-50*(-280)*10^3==>14 kW
Case (2)
dT/dx= (-10+30)/0.35==> 80 K/m
q_x =-50*(80)*10^3==>-4 kW
Case (2)
dT/dx= (-10+30)/0.35==> 80 K/m
q_x =-50*(80)*10^3==>-4 kW
Case (3)
q_x =-50*(160)*10^3==>-8 kW
T2=T1+dT/dx*L=70+160*0.25==> 110° C
Case (4)
q_x =-50*(-80)*10^3==>4 kW
T1=T2-dT/dx*L=40+80*0.25==> 60° C
Case (5)
q_x =-50*(200)*10^3==>-10 kW
T1=T2-dT/dx*L=30-200*0.25==> -20° C
note:
all graph are attached
Answer:
area = 5733.33 cm²
length = 5.47 ×
cm
Explanation:
Given data
density = 19.32 g/cm³
mass = 33.16 g
thickness = 3.000 µm = 3 ×
cm
radius r = 1.000 µm = 1 × cm
to find out
area of the leaf and length of the fiber
solution
we know volume formula that is
volume = mass / density
volume = 33.16 / 19.32
volume = 1.72 cm³
we know that volume = thickness × area
so area
area = volume / thickness
area = 1.72 / 3 ×
area = 5733.33 cm²
and
we know volume = πr²L
so L = volume / πr²
length = 1.72 / π(1×)²
length = 5.47 × cm
