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3 years ago

6

Can someone help me with this question

1 answer:

Anna71 [15]3 years ago

7 0

Answer:

Ionic- Ion

Covalent- Molecules

Explanation:

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A 90 kg body is taken to a planet where the acceleration due to

yawa3891 [41]

Answer:

225 kg.

Explanation:

Since the gravity is 2.5 times than that of the Earth, g on that planet = (10 * 2.5) m/s = 25 m/s.

Hence, the weight of the body would be (90 * 2.5) kg, aka 225 kg.

Hope this helped!

6 0

3 years ago

A circus performer stretches a tightrope between two towers. He strikes one end of the rope and sends a wave along it toward the

IgorC [24]

Explanation:

The given data is as follows.

Distance (s) = 20 m

time (t) = 0.775 s

Also, it is given that mass per 1 meter length (m) = 0.300 kg

Formula to calculate the velocity is as follows.

Velocity (v) = $\frac{s}{t}$

Putting the given values into the above formula as follows.

v = $\frac{s}{t}$

= $\frac{20 m}{0.775 s}$

= 25.80 m/s

We know that,

v = $\sqrt{\frac{T}{m}}$

Taking square on both the sides, the formula will become as follows.

T = $mv^{2}$

= $0.3 kg \times 25.80$

= 199.692 N

Therefore, we can conclude that tension in the given tightrope is equal to 199.692 N .

5 0

3 years ago

Which of the following is true of alternating current? Select all that apply.

Nitella [24]

Answer:

The correct option is (C).

Explanation:

Electric current can be direct or alternating.

The direct current flows only in one direction. It is unidirectional.

The alternating current or an C current reverse its direction periodically.

So, the correct statement regarding the alternating current is (c) i.e. Electrons reverse direction periodically.

7 0

3 years ago

A comet is traveling through space with speed 3.01 ✕ 104 m/s when it encounters an asteroid that was at rest. The comet and the

Tcecarenko [31]

Answer: $8.493(10)^{-3} m/s$

Explanation:

According to the conservation of linear momentum principle, the initial momentum $p_{i}$ (before the collision) must be equal to the final momentum $p_{f}$ (after the collision):

$p_{i}=p_{f}$ (1)

In addition, the initial momentum is:

$p_{i}=m_{1}V_{1}+m_{2}V_{2}$ (2)

Where:

$m_{1}=1.71(10)^{14} kg$ is the mass of the comet

$m_{2}=6.06(10)^{20} kg$ is the mass of the asteroid

$V_{1}=3.01(10)^{4} m/s$ is the velocity of the comet, which is positive

$V_{2}=0 m/s$ is the velocity of the asteroid, since it is at rest

And the final momentum is:

$p_{f}=(m_{1}+m_{2})V_{f}$ (3)

Where:

$V_{f}$ is the final velocity

Then :

$m_{1}V_{1}+m_{2}V_{2}=(m_{1}+m_{2})V_{f}$ (4)

Isolating $V_{f}$ :

$V_{f}=\frac{m_{1}V_{1}}{m_{1}+m_{2}}$ (5)

$V_{f}=\frac{(1.71(10)^{14} kg)(3.01(10)^{4} m/s)}{1.71(10)^{14} kg+6.06(10)^{20} kg}$

Finally:

$V_{f}=8.493(10)^{-3} m/s$ This is the final velocity, which is also in the positive direction.

8 0

4 years ago

You work for the city water department and need to pump 3400 liters/minute of water from a tank at ground level into a vented (i

umka21 [38]

Answer:

$P_E=46.2778\ kW$

$v=1.804\ m.s^{-1}$

Explanation:

Given:

flow rate of water, $\dot{V}=3400\ L.min^{-1}=3.4\ m^3.min^{-1}$

<em>∵Density of water is 1 kg per liter</em>

∴mass flow rate of water, $\dot{m}=3400\ kg.min^{-1}$

height of pumping, $h=75\ m$

efficiency of motor drive, $\eta=0.9$

diameter of pipe, $D =0.2\ m$

<u>Now the power required for pumping the water at given conditions:</u>

$P=\dot{m}.g.h$

$P=\frac{3400}{60} \times 9.8\times 75$

$P=41650\ W$

<u>Hence the electric power required:</u>

$P_E \times \eta=P$

$P_E \times 0.9=41650$

$P_E=46.2778\ kW$

<u>Flow velocity is given as:</u>

$v=\dot{V}\div a$

where: a = cross sectional area of flow through the pipe

$v=\frac{3.4}{60}\div (\pi.\frac{0.2^2}{4} )$

$v=1.804\ m.s^{-1}$

3 0

3 years ago