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3 years ago

True or false : In crystalline solids the particles are not arranged in a regular pattern

Physics

2 answers:

dexar [7]3 years ago

6 0

The answer is ..... False

IrinaK [193]3 years ago

3 0

False. They are arranged in a structure called a crystal lattice

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Two trains are headed towards each other on the same track unbeknownst to the engineers. One departs San Francisco. Its average

aalyn [17]

Answer:

7,166 hrs =430 minutes

Explanation:

Since both train are on the same track, going one towards the other, the relative speed is the addition of both, then the time they need to meet, and consistently crash, is the time that (65mph + 55 mph)=120mph need to travel the total distance of 860 miles, of course in this case one part is traveled by the first train and the rest by the other. Then to find the time we use a three rule

1 h --->120mi

X ---->860mi, then X=(860 mi* 1h)/120 mi = 43/6 hrs= 7,16666 hrs, turning this into minutes need that we notice 1h=60min, then 43/6 hrs *60 min/hrs = 430 minutes.

7 0

3 years ago

A 26 foot ladder is lowered down a vertical wall at a rate of 3 feet per minute. The base of the ladder is sliding away from the

lakkis [162]

Answer:

(i) 7.2 feet per minute.

(ii) No, the rate would be different.

(iii) The rate would be always positive.

(iv) the resultant change would be constant.

(v) 0 feet per min

Explanation:

Let the length of ladder is l, x be the height of the top of the ladder from the ground and y be the length of the bottom of the ladder from the wall,

By making the diagram of this situation,

Applying Pythagoras theorem,

$l^2 = x^2 + y^2-----(1)$

Differentiating with respect to t ( time ),

$0=2x\frac{dx}{dt} + 2y\frac{dy}{dt}$ ( l = 26 feet = constant )

$\implies 2y\frac{dy}{dt} = -2x\frac{dx}{dt}$

$\implies \frac{dy}{dt}=-\frac{x}{y}\frac{dx}{dt}$

We have,

$y = 10, \frac{dx}{dt}= -3\text{ feet per min}$

$\frac{dy}{dt}=\frac{3x}{10}-----(X)$

(i) From equation (1),

$26^2 = x^2 + 10^2$

$676=x^2 + 100$

$576 = x^2$

$\implies x = 24\text{ feet}$

From equation (X),

$\frac{dy}{dt}=\frac{3\times 24}{10}=7.2\text{ feet per min}$

(ii) From equation (X),

$\frac{dy}{dt}\propto x$

Thus, for different value of x the value of $\frac{dy}{dt}$ would be different.

(iii) Since, distance = Positive number,

So, the value of y will always a positive number.

Thus, from equation (X),

The rate would always be a positive.

(iv) The length of the ladder is constant, so, the resultant change would be constant.

i.e. x = increases ⇒ y = decreases

y = decreases ⇒ y = increases

(v) if ladder hit the ground x = 0,

So, from equation (X),

$\frac{dy}{dt}=0\text{ feet per min}$

3 0

3 years ago

If you are reading this please help ASAP !!!!!

NISA [10]

Answer:

Explanation:

5 0

3 years ago

We go out to sunbathe on a warm summer day. If we soak up 80 British thermal units per hour [BTU/h] of energy, how much will t

Jlenok [28]

Answer:

0.62127°C

Explanation:

$1\ BTU=1055\ J$

$80\ BTU/h=80\times 1055=84400\ J/h$

Heat absorbed by body in 2 hours

$Q=84400\times 2\\\Rightarrow Q=168800\ J$

m = Mass of person = 65000 g

c = Specific heat of water = 4180 J/kg°C

$\Delta T$ = Change in temperature

Heat is given by

$Q=mc\Delta T\\\Rightarrow 168800=65\times 4180\times \Delta T\\\Rightarrow \Delta T=\dfrac{168800}{65\times 4180}\\\Rightarrow \Delta T=0.62127\ ^{\circ}C$

The increase in temperature will be 0.62127°C

7 0

3 years ago

Question is in the uploaded photo

ss7ja [257]

Answer:

1) Mass of the string = 0.0267kg

Explanation:

1) In the above question, we are given:

Length of guitar string = 60cm

Wave speed = 30.0m/s

Tension = 50N

9.81 N = 1 kg

50N = 50/9.81

= 5.10kg

We have the formula

v = √(F/μ)

Where F = the tension in the string in newtons,

v = the wave speed in m/s

μ = the mass per unit length of the string in kg/m

The formula for μ is derived as

v = √(F/μ)

Square both sides

v² = [√(F/μ)]²

v² = F/μ

μ = F/v²

From the question,

μ = 40/ 30.0²

μ = 0.044kg/m

To calculate the mass of the string we use the formula

μ = Mt / Lt = total mass/total length.

Total length = 60cm

In meters = 0.60m

0.044kg/m = Mt/ 0.60m

Mt = 0.0266666667kg

Mass of the string = Approximately 0.0267kg

4 0

3 years ago