A low-resistance path in a circuit, commonly called a ____

When compared to early vehicles, modern vehicles do not have?

KIM [24]

Modern vehicles do not have steam or coal engines

6 0

3 years ago

Technician A says that latent heat is hidden heat and cannot be measured on a thermometer. Technician B says that latent heat is

AysviL [449]

Answer: C

Both A and B are correct

Explanation:

Latent heat is the hidden heat.

Latent heat is the heat energy required to change one state of matter to another state of matter without change in temperature. For example, solid state to liquid state, or liquid state to gaseous state.

Thermometer can not detect the latent heat. That is why it is called hidden heat.

If Technician A says that latent heat is hidden heat and cannot be measured on a thermometer. And Technician B says that latent heat is hidden heat that is required for a change of state of matter, then we can therefore conclude that both Technician A and Technician B are correct.

5 0

3 years ago

Explain 3 types of lubrication occurs in bearings?

Angelina_Jolie [31]

Answer:

The three types of lubrication occurred in the bearing are:

When the lubrication occur in the bearing it play an important role in the rolling life of bearing element. Basically, lubricant task is to reduced the friction.

1) Grease lubricant: Grease contain various type of additives which help in enhance the performance. It consist of oil where thickness are added as, this thickness improved the characteristics of grease.

2) Oil lubricant: This is used to reduced or minimized the friction and the lubricant oil is used to in those vehicles when they are motorized. Bearing lubricant oil is used to higher the speed capability.

3) Solid films: These are non fluid coating surface that are applied in the friction surface for prevention. It is used in very extreme situation where oil and grease types of lubricant does not work.

8 0

3 years ago

What is substructure work?

o-na [289]

The answer is: Work below ground level.

5 0

3 years ago

The screw of shaft straightener exerts a load of 30 as shown in Figure . The screw is square threaded of outside diameter 75 mm

kykrilka [37]

Answer:

See calculation below

Explanation:

Given:

W = 30 kN = 30x10³ N

d = 75 mm

p = 6 mm

D = 300 mm

μ = tan Φ = 0.2

1. Force required at the rim of handwheel 

Let P₁ = Force required at the rim of handwheel

Inner diameter or core diameter of the screw = dc = do - p = 75 - 6 = 69 mm

Mean diameter of screw: *d = $\frac{do + dc}{2}$ = (75 + 69) / 2 = 72 mm

and

tan α = p / πd = 6 / (π x 72) = 0.0265

∴ Torque required to overcome friction at he threads is T = P x d/2

T = W tan (α + Ф) d/2

T = $W(\frac{tan \alpha + tan \theta}{1 - tan \alpha + tan \theta } ) * \frac{d}{2}$

T = 30x10³ * ((0.0265 + 0.2) / (1 - 0.0265 x 0.2)) x 72/2

T = 245,400 N-mm

We know that the torque required at the rim of handwheel (T)

245,400 = P1 x D/2 = P1 x (300/2) = 150 P1

P1 = 245,400 / 150

P1 = 1636 N

2. Maximum compressive stress in the screw

30x10³

Qc = W / Ac = -------------- = 8.02 N/mm²

π/4 * 69²

Qc = 8.02 MPa

Bearing pressure on the threads (we know that number of threads in contact with the nut)

n = height of nut / pitch of threads = 150 / 6 = 25 threads

thickness of threads, t = p/2 = 6/2 = 3 mm

bearing pressure on the threads = Pb = W / (π d t n)

Pb = 30 x 10³ / (π * 72 * 3 * 25)

Pb = 1.77 N/mm²

Max shear stress on the threads = τ = 16 T / (π dc³)

τ = (16 * 245,400) / ( π * 69³ )

τ = 3.8 M/mm²

*the mean dia of the screw (d) = d = do - p/2 = 75 - 6/2 = 72

∴max shear stress in the threads τmax = 1/2 * sqrt(8.02² + (4 * 3.8²))

τmax = 5.5 Mpa

3. efficiency of the straightener

To = W tan α x d/2 = 30x10³ * 0.0265 * 72/2 = 28,620 N-mm

∴Efficiency of the straightener is η = To / T = 28,620 / 245,400

η = 0.116 or 11.6%

4 0

3 years ago

A low-resistance path in a circuit, commonly called a _____ can cause a circuit breaker to trip