Answer:
4. It is the force of the road on the tires (an external force) that stops the car.
Explanation:
If there is no friction between the road and the tires, the car won't stop.
You can see this, for example, when there is ice on the road. You can still apply the brakes (internal force), but since there is no friction (external force) the car won't stop.
The force of the brakes on the wheels is not what makes the car stop, it is the friction of the road against still tires that makes it stop.
I think:
In motion- 40
Not moving- 20
Answer:
A) 26V
Explanation:
(a) the potential difference between the plates
Initial capacitance can be calculated using below expresion
C1= A ε0/ d1
Where d1= distance between = 2.70 mm= 2.70× 10^-3 m
ε0= permittivity of space= 8.85× 10^-12 Fm^-1
A= area of the plate = 7.90 cm2 = 7.90 ×10^-4 m^2
If we substitute the values we
C1= A ε0/ d1
=( 7.90 ×10^-4 × 8.85× 10^-12 )/2.70× 10^-3
C1=2.589 ×10^-12 F= 2.59 pF
Initial charge can be determined using below expresion
q1= C1 × V1
V1=2.589 ×10^-12 F
V1= voltage=7.90 V
If we substitute we have
q1= 2.589 ×10^-12 × 7.90
q1= 20.45×10^-12C
20.45 pC
Final capacitance can be calculated as
C2= A ε0/ d2
d2=8.80 mm= /8.80× 10^-3
7.90 ×10^-4 × 8.85× 10^-12 )/8.80× 10^-3
C1=0.794 ×10^-12 F= 0.794 pF
Final charge= initial charge
q2=q1 (since the battery is disconnected)
q2=q1= 20.45 pC
Final potential difference
V2= q/C2
= 20.45/0.794
= 26V
Answer:
✓ A cyclone device accumulates fine particulates from the air by making a dirty air stream flow in a spiral path inside a cylindrical chamber.
✘ It consists of several long and narrow fabric filter bags suspended upside-down in a large enclosure.
✓ When dirty air enters the chamber, the larger particulates strike the chamber wall and fall into a conical dust hopper at the bottom.
✘ Fans blow dirt-filled air upward from the bottom of the enclosure, trapping dirt particles inside the filter bags and releasing clean air from the top.
✓ The top of the chamber has an outlet that lets out cleaned air.
Basically, any of these choices that have the word "filter" are wrong. The point of the cyclone device is to separate the particles without the use of filters. You can tell the right answers based on the picture attached below.
Answer:
15.07 ksi
Explanation:
Given that:
Pitch (P) = 5 teeth/in
Pressure angle (
) = 20°
Pinion speed (
) = 2000 rev/min
Power (H) = 30 hp
Teeth on gear (
) = 50
Teeth on pinion (
) = 20
Face width (F) = 1 in
Let us first determine the diameter (d) of the pinion.
Diameter (d) =
=
= 4 in
From the values of Lewis Form Factor Y for (
) = 20 ; at 20°
Y = 0.321
To find the velocity (V); we use the formula:


V = 2094.40 ft/min
For cut or milled profile; the velocity factor
can be determined as follows:


= 2.0472
However, there is need to get the value of the tangential load
, in order to achieve that, we have the following expression




Finally, the bending stress is calculated via the formula:



15.07 ksi
∴ The estimate of the bending stress = 15.07 ksi