Of the superalloys, the cobalt-base types are the easiest to braze. True or False?

A new roller coaster contains a loop-the-loop in which the car and rider are completely upside down. If the radius of the loop i

Oduvanchick [21]

To solve this problem it is necessary to apply the concepts based on Newton's second law and the Centripetal Force.

That is to say,

$F_c = F_w$

Where,

$F_c =$ Centripetal Force

$F_w =$ Weight Force

Expanding the terms we have to,

$mg = \frac{mv^2}{r}$

$gr = v^2$

$v = \sqrt{gr}$

Where,

r = Radius

g = Gravity

v = Velocity

Replacing with our values we have

$v = \sqrt{(9.8)(11.8)}$

$v = 10.75m/s$

Therefore the minimum speed must the car traverse the loop so that the rider does not fall out while upside down at the top is 10.75m/s

5 0

3 years ago

The total amount of power that a star radiates is called its

Ede4ka [16]

Luminosity is the total amount of power a star radiate I think :)

3 0

3 years ago

A carnot heat engine receives 600 kj of heat from a source of unknown temperature and rejects 175 kj of it to a sink at 20°c. de

oee [108]

(b) 71%

The thermal efficiency of a Carnot heat engine is given by:

$\eta = \frac{W}{Q_{in}}$

where

W is the useful work done by the engine

$Q_{in}$ is the heat in input to the machine

In this problem, we have:

$Q_{in}=600 kJ$ is the heat absorbed

$W=600 kJ-175 kJ=425 kJ$ is the work done (175 kJ is the heat released to the sink, therefore the work done is equal to the difference between the heat in input and the heat released)

So, the efficiency is

$\eta = \frac{425 kJ}{600 kJ}=0.71 = 71\%$

(a) $737^{\circ}C$

The efficiency of an engine can also be rewritten as

$\eta = 1-\frac{T_C}{T_H}$

where

$T_C$ is the absolute temperature of the cold sink

$T_H$ is the temperature of the source

In this problem, the temperature of the sink is

$T_C = 20^{\circ}C + 273=293 K$

So we can re-arrange the equation to find the temperature of the source:

$T_H = \frac{T_C}{1-\eta}=\frac{293 K}{1-0.71}=1010 K\\T_H = 1010 K - 273=737^{\circ}C$

7 0

3 years ago

What electromagnetic radiations can the human bodies senses detect??

BlackZzzverrR [31]

Answer:

Human senses include the ability to detect electromagnetic waves in the 3800-7600 angstrom range, air waves of 15 to 20,000 beats per second, air-borne and liquid-borne molecules of proper size, quantity and configuration, and to generate nerve impulses triggered by objects impinging on body surfaces with enough force

4 0

3 years ago

The current in a resistor is 3.0 A, and its power is 60 W. What is the voltage?

kkurt [141]

Answer:

I font now but I think its 2.0 + 78 w -60

8 0

2 years ago