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2 years ago

8

Which earthquake scale is based mostly on human opinion and perception of recent events? richter scale moment magnitude scale mo

dified mercalli scale fujita scale saffir-simpson scale?

1 answer:

77julia77 [94]2 years ago

8 0

I really don’t know this

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If the copper is drawn into wire whose diameter is 6.50 mm, how many feet of copper can be obtained from the ingot? the density

Kobotan [32]

Assume that an ingot of copper has a mass of 9.1 kg or 9100 g.

The cross-sectional area of the copper wire with diameter of 6.5 mm (or 0.65 cm) is
A = (π/4)*(0.65 cm)² = 0.3318 cm²

The density of copper is given as 8.94 g/cm³.
If the length of copper wire is L cm, then
(0.3318 cm²)*(L cm)*(8.94 g/cm³) = 9100 g
L = 9100/(0.3318*8.94) = 3.0678 x 10³ cm

Note that
1 cm = 1/2.54 in = 1/2.54 in = 0.3937 in
= 0.3937/12 = 0.03281 ft

Therefore
L = (3.0678 x 10³ cm)*(0.03281 ft/cm) = 100.65 ft

Answer: 100.65 ft

6 0

3 years ago

A 1000 kg car is rolling slowly across a level surface at 1m/s, heading toward a group of small innocent children.

Ne4ueva [31]

Answer:

The force is -1620.73 N.

Explanation:

Given that,

Mass of car = 1000 kg

Velocity = 1 m/s

Distance = 2 m

Angle = 30°

We need to calculate the force

Using formula of work done

$W_{net}=K_{f}-K_{i}$

$F\times d=K_{f}-K_{i}$

$Fd\cos\theta=-K_{i}$

$F=\dfrac{-K_{f}}{d\cos\theta}$

$F=-\dfrac{\dfrac{1}{2}mv^2}{d\cos\theta}$

Put the value into the formula

$F=-\dfrac{\dfrac{1}{2}\times1000\times(1)^2}{2\times\cos30}$

$F=-1620.73\ N$

Hence, The force is -1620.73 N.

7 0

3 years ago

Read 2 more answers

Read the following scenario.

andrew-mc [135]

Answer:

Their experimental design lacks control group

Explanation:

Based on what I read, the scientists don't have a control group as one of the main groups thus they cannot, in scientific sense, say that the medicine is better or worse. You always need a control group receiving no intervention because then we can compare groups and assess the effectiveness of that intervention (in our case if we had control group vs people who received the medicine, we could see if the people who received the medicine had improved condition etc when compared to participants who did not receive anything)

5 0

2 years ago

Read 2 more answers

During a medieval siege of a castle, the attacking army uses a trebuchet to heavy stones at the castle the trebuchet launches th

vlada-n [284]

Answer:

Explanation:

The question relates to time of flight of a projectile .

Time of flight = 2 u sinθ / g

u is speed of projectile , θ is angle of projectile

= 2 x 48.5 sin42 / 9.8

= 6.6 seconds .

Maximum height attained

= u² sin²θ / g

= 48.5² sin²42 / 9.8

= 107.47 m .

7 0

2 years ago

1. What is the relationship between wavelength and the penetrating power of an electromagnetic wave?

Andreyy89

#1

As we know that energy of electromagnetic wave is given by

$E = \frac{hc}{\lambda}$

so here we know that penetrating power will directly depends on its energy and energy inversely depends on wavelength

So here we can say correct answer will be

C) The penetrating power decreases as the wavelength increases.

#2

Speed of sound is maximum in solids and minimum in gas

so here as ice melts into water the speed of sound must have to decrease

so correct answer will be

D) The speed of sound would decrease because sound travels faster through solids than liquids.

#3

mechanical waves required medium to travel while non mechanical waves do not require any medium to travel

so here correct answer will be

A) sound

6 0

3 years ago