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3 years ago

Which of the following is an ionic compound ? A. Gold

1 answer:

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Among the given choices, the ionic compound is D. Magnesium Chloride (<span>MgCl2</span>) where magnesium has a +2 charge while chloride has a -1 charge. Ionic compounds are chemical compounds comprising of ions held together by electrostatic forces named as ionic bonding.

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How does Doppler ultrasound technology differ from ultrasound technology

patriot [66]

Answer:

. Doppler ultrasound is based on absorption of sound, and other

ultrasound technology is based on reflection.D.

Explanation:

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3 years ago

Read 2 more answers

A student heats a piece of aluminum, with specific heat 0.900 J/gºC, in

tankabanditka [31]

Answer:

my bad i need points good luck

Explanation:

adawd

8 0

3 years ago

A pendulum has 918 J of potential energy at the highest point of a swing. How much kinetic energy will it have at the bottom of

GREYUIT [131]

The kinetic energy at the bottom of the swing is also 918 J.

Assume the origin of the coordinate system to be at the lowest point of the pendulum's swing. A pendulum, when raised to the highest point has potential energy since it is raised to a height h above the origin. At the highest point, the pendulum's velocity becomes zero, hence it has no kinetic energy. Its energy at the highest point is wholly potential.

When the pendulum swings down from its highest position, it gains velocity. Hence a part of its potential energy begins to convert itself into kinetic energy. If no dissipative forces such as air resistance exist, then, the law of conservation of energy can be applied to the swing.

Under the action of conservative forces, the total mechanical energy of a system remains constant.This means that the sum of the potential and kinetic energies of a body remains constant.

When the pendulum reaches the lowest point of its swing, it is at the origin of the chosen coordinate system. Its vertical displacement from the origin is zero, hence its potential energy with respect to the origin is zero. Therefore the entire potential energy of 918 J should have been converted into kinetic energy, according to the law of conservation of energy.

Thus, the kinetic energy of the pendulum at the lowest point of its swing is equal to the potential energy it had at its highest point, which is equal to <u>918 J.</u>

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3 years ago

A parachutist weighs 1000N. when she opens her parachute, it pulls upwards on her with a force of 2000N. (a) draw a diagram to s

Nataly_w [17]

(a) Find free-body diagram in attachment (please rotate the picture, such that R points upward and mg points downward)

There are only two forces acting on the parachutist:

- Its weight, downward, of magnitude 1000 N, labelled with "mg" in the diagram (where m = mass of the parachutist, g = acceleration of gravity)

- The air resistance, upward, of magnitude 2000 N, labelled with "R" in the diagram

As the air resistance is larger than the weight, in the diagram it is represented with a longer arrow, in order to show the difference in magnitude.

(b) 1000 N, upward

By taking upward as positive direction, we can rewrite the two forces as:

R = +2000 N

mg = -1000 N

Where we have written the weight as a negative number, since its direction is downward.

Therefore, the net force on the parachutist will be

F = R + mg = +2000 + (-1000) = +1000 N

And the positive sign indicates that the resultant force is upward.

(c) The parachutist will be accelerated upward (= he/she will slow down)

We can answer this part by applying Newton's second law, which is summarized by the following:

$F=ma$ (1)

where

F is the resultant force on the body

m is its mass

a is its acceleration

For the parachutist in this problem, the mass is

$m=\frac{mg}{g}=\frac{1000 N}{9.8 N/kg}=102 kg$

Therefore, using (1), we find the acceleration of the parachutist:

$a=\frac{F}{m}=\frac{+1000}{102}=+9.8 m/s^2$

Where the positive sign indicates that the acceleration is upward. Therefore, the parachutist will be accelerated upward, which means that he/she will slow down, since its direction of motion was downward.

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3 years ago

The magnetic field of the brain has been measured to be approximately 3.0×10−12T. Although the currents that cause this field ar

saw5 [17]

Answer:

I = 3.82 x 10^(−7) A

Explanation:

The formula for magnetic field at the centre of a loop is given as;

B = μI/2R

Where μ is a magnetic constant with a value of 12.57 × 10^(−7) H/m.

I = current

R = Radius = 16/2 = 8cm or 0.08m

B = 3.0×10^(−12) T

So making I the subject of the formula, we obtain ;

I = 2RB/μ

Thus, I = [2 x 0.08 x 3.0×10^(−12)]/12.57 × 10^(−7)

I = 3.82 x 10^(−7) A

7 0

2 years ago