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3 years ago

Which of the following is an example of acceleration? Select one:

1 answer:

8 0

Acceleration' is any change in the speed or direction of motion. we can look through the choices:
A). /
B). No. Neither speed nor direction changed.
C). /
D). Yes. The boy's direction changed.

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The Hubble Space Telescope (HST) orbits 569 km above Earth’s surface. If HST has a tangential speed of 7,750 m/s, how long is HS

deff fn [24]

Answer: 5,640 s (94 minutes)

Explanation:

the tangential speed of the HST is given by

$v=\frac{2\pi r}{T}$ (1)

where

$2\pi r$ is the length of the orbit

r is the radius of the orbit

T is the orbital period

In our problem, we know the tangential speed: $v=7,750 m/s$ . The radius of the orbit is the sum of the Earth's radius and the distance of the HST above Earth's surface:

$r=6.38\cdot 10^6 m+569,000 m=6.95\cdot 10^6 m$

So, we can re-arrange equation (1) to find the orbital period:

$T=\frac{2 \pi r}{v}=\frac{2 \pi (6.95\cdot 10^6 m/s)}{7,750 m/s}=5,640 s$

Dividing by 60, we get that this time corresponds to 94 minutes.

6 0

3 years ago

Read 2 more answers

How do we maintain heat in our body ?

zysi [14]

Answer:

When heat activates sweat glands, these glands bring that water, along with the body's salt, to the surface of the skin as sweat. Once on the surface, the water evaporates. Water evaporating from the skin cools the body, keeping its temperature in a healthy range.

Explanation:

The system can respond to internal and external influences and make adjustments to keep your body within a degree or two of your normal. The hypothalamus and your autonomic nervous system work with your skin, sweat glands, muscles and even your blood vessels to keep your temperature normal. As in other mammals, thermoregulation is an important aspect of human homeostasis. Most body heat is generated in the deep organs, especially the liver, brain, and heart, and in contraction of skeletal muscles. Some nuts like peanuts, almonds, cashews, pistachios, and dates are also beneficial in winter. These nuts speed up your metabolism and increase your body temperature, eventually making you feel hot.

7 0

3 years ago

An archer shoots an arrow with a mass of 45.0 grams from bow pulled

Sladkaya [172]

Answer:

The force the archer need to pull in order to achieve the height is approximately 101.8 N

Explanation:

By energy conservation principle, puling an elastic bow with a force, for a given distance, performs work which is converted to the potential energy of the arrow at height

The given parameters are;

The mass of the arrow, m = 45.0 grams = 0.045 kg

The distance the elastic bow is pulled, d = 65.0 cm = 0.65 m

The height at which the arrow is reaches, h = 150.0 meters

Let 'F', represent the force the archer need to pull in order to achieve the height

Work done, W = Force × Distance moved in the direction of the force

Therefore;

The work done in pulling the arrow, W = F × d

By energy conservation, we have;

The work done in pulling the arrow, W = The potential energy gained by the arrow, P.E.

W = P.E.

The potential energy gained by the arrow, P.E. = m·g·h

Where;

m = The mass of the arrow

g = The acceleration due to gravity = 9.8 m/s²

h = The height the arrow reaches

∴ by plugging in the values, P.E. = 0.045 kg ×9.8 m/s² × 150 m = 66.15 J

W = F × d = F × 0.065 m

Also, W = P.E. = 66.15 J

∴ W = F × 0.065 m = 66.15 J

F × 0.065 m = 66.15 J

F = 66.15 J/(0.65 m) = 1323/13 N ≈ 101.8 N

The force the archer need to pull in order to achieve the height, F ≈ 101.8 N.

3 0

3 years ago

A rod of length 0.82 m, rotating with an angular speed, 4.2 rad/s, about axes that pass perpendicularly through one end, has a m

mariarad [96]

Answer:

Explanation:

KE = ½Iω²

ΚΕ = ½(mL²/3)ω²

ΚΕ = ½(0.63(0.82²)/3)4.2²

ΚΕ = 1.24541928

KE = 1.2 J

5 0

2 years ago

What characteristics distinguish the inner planets in the solar system from the outer planets?

Julli [10]

The four inner plants have shorter orbits slower spin ,no rings ,and they are made up of rock and metal
The outer plants are made up of hydrogen and helium, so they are called gas giants

Explanation:

hope it is the right answer

5 0

3 years ago