Which of the following expressions is equivalent to the expression 2(x + 5)? x + 7 x + 10 2x + 5 2x + 10

If a hot air balloon is seen rising above the top of a hill, what is the top of the hill called? Question 2 options: delta point

timofeeve [1]

If a hot air balloon has shown rising above the top of a hill, the top of the hill is considered as a reference point.

<h2>Reference Point:</h2>

It is a point that is used to standardize a experiment. The reference point is a constant point.

In the given problem:

The hot air balloon is rising above the top of the hill. Here, the hill is a standard point that has a fixed (constant) height.

Some other reference points are the top of the Eifel Tower or a famous shop which a person use to denote a certain distance.

Therefore, "If a hot air balloon has shown rising above the top of a hill" the top of the hill is considered as a reference point.

Learn more about Reference Point:

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5 0

2 years ago

An airplane pilot wishes to fly directly westward. According to the weather bureau, a wind of 75.0km/hour is blowing southward.

qaws [65]

Answer:

a) correct answer is C , b) 14º from the west to the north, c) v_{1g} = 300.79 km / h

Explanation:

This is a relative speed exercise using the addition of speeds.

1) when it is not specified regarding what is being measured, the medicine is carried out with respect to the Z Earth, therefore the correct answer is C

2 and 3) In this case we must compose the speed using the Pythagorean Theorem.

$v_{1a}$ ² = $v_{1g}$ ² + $v_{ag}$ ²

where v_{1a} is the speed of the airplane with respect to the air, v_{1g} airplane speed with respect to the Earth, v_{ag} air speed with respect to the Earth

in this case let's clear the speed of the airplane with respect to the Earth

v_{1g} = √(v_{1a}² - v_{ag}²)

v_{1g} = √ (310² - 75²)

v_{1g} = 300.79 km / h

we find the direction of the airplane using trigonometry

sin θ = v_{ag} / v_{1a}

θ = sin⁻¹ (v_{ag} /v_{1a})

θ = sin⁻¹ (75/310)

θ= 14º

the pilot must direct the aircraft at an angle of 14º from the west to the north

7 0

3 years ago

Which of the following has the most potential energy?

Alex

A Car at the top of a hill.

It is because in that case, produce of mass and height is highest which is directly proportional to potential energy

In short, Your Answer would be Option A

Hope this helps!

3 0

3 years ago

Read 2 more answers

A volleyball player bumps a ball across a net with the velocity and angle shown below. What is the maximum height of the ball?

Marrrta [24]

Answer:

D. 12.4 m

Explanation:

Given that,

The initial velocity of the ball, u = 18 m/s

The angle at which the ball is projected, θ = 60°

The maximum height of the ball is given by the formula

h = u² sin²θ/2g m

Where,

g - acceleration due to gravity. (9.8 m/s)

Substituting the values in the above equation

h = 18² · sin²60 / 2 x 9.8

= 18² x 0.75 / 2 x 9.8

= 12.4 m

Hence, the maximum height of the ball attained, h = 12.4 m

6 0

3 years ago

Transcranial magnetic stimulation (TMS) is a noninvasive technique used to stimulate regions of the human brain. A small coil is

attashe74 [19]

Answer:

0.125 volts

Explanation:

The induced emf can be sufficient to stimulate neuronal activity.

One such device generates a magnetic field within the brain that rises from zero to 1.5 T in 120 ms.

We need to find the induced emf within a circle of tissue of radius 1.6 mm and that is perpendicular to the direction of the field. The formula for the induced emf is given by :

$\epsilon=-\dfrac{d\phi}{dt}$

Where

$\phi$ is magnetic flux

So,

$\epsilon=-\dfrac{d(BA)}{dt}\\\\=2\pi r\times \dfrac{dB}{dt}\\\\=2\pi \times 1.6\times 10^{-3}\times \dfrac{1.5-0}{120\times 10^{-3}}\\\\=0.125\ V$

So, the induced emf is equal to 0.125 volts.

7 0

3 years ago