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Mazyrski [523]
3 years ago
12

g An arrow is shot straight up in the air at an initial speed of 15.5 m/s. After how much time is the arrow moving downward at a

speed of 5.20 m/s
Physics
1 answer:
Sati [7]3 years ago
5 0

Answer:

2.11 seconds

Explanation:

We use the kinematic equation for the velocity in a constantly accelerated motion under the acceleration of gravity (g):

v_f=v_i-g*t\\-5.2 = 15.5 - 9.8\,t\\9.8 \,t= 15.5 + 5.2\\t = 20.7/9.8\\t = 2.11 \,\,sec

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3. Sodium-24 has a half-life of 15 hours. If a sample of sodium-24 has an
sattari [20]

Answer:

See explanation

Explanation:

From the formula;

0.693/t1/2 = 2.303/t log (Ao/A)

t1/2 = half life of Sodium-24

Ao = initial activity of Sodium-24

A= activity of Sodium-24 at time = t

So,

0.693/15 = 2.303/15 log (800/A)

0.0462 = 0.1535  log (800/A)

0.0462/0.1535 =  log (800/A)

0.3 = log (800/A)

Antilog(0.3) =  (800/A)

1.995 =  (800/A)

A = 800/1.995

A = 401 Bq

ii) 0.693/15 = 2.303/30 log (800/A)

0.0462 = 0.0768 log (800/A)

0.0462/0.0768 =  log (800/A)

0.6 =  log (800/A)

Antilog (0.6) =  (800/A)

3.98 =  (800/A)

A = 800/3.98

A = 201 Bq

iii)

0.693/15 = 2.303/45 log (800/A)

0.0462 = 0.0512  log (800/A)

0.0462/0.0512  =  log (800/A)

0.9 = log (800/A)

Antilog (0.9) =  (800/A)

7.94 = (800/A)

A = 800/7.94

A= 100.8 Bq

iv)

0.693/15 = 2.303/60 log (800/A)

0.0462 = 0.038 log (800/A)

0.0462/0.038 = log (800/A)

1.216 = log (800/A)

Antilog(1.216) = (800/A)

16.44 = (800/A)

A = 800/16.44

A = 48.66 Bq

3 0
2 years ago
According to Bohr each orbit an electron could travel in had a certain amount of ________ associated with it.
Lena [83]
The awnser to your problem would be a as in energy
6 0
2 years ago
Classify each possible hypothesis about a medicinal aloe vera plant as falsifiable or non-falsifiable.
pychu [463]

Answer:

Aloe vera is a succulent plant species ( with fleshy water storing tissue) belonging to the genus Aloe.

It is used in many products ( including beverages, cosmetic products as gel, medicinal ointments). Its juice is quite bitter in taste. It is known to be the best skin moisturizer and can be used for healing wounds by enhancing the renewal of damaged cells. It is also used as an anticarcinogen, thus reduces the chances of cancer.

Thus, the given hypothesis can be classified as  falsifiable ( which is proven wrong) or non-falsifiable ( which is proven right) in the following way-

Falsifiable-

Aloe vera juice tastes  better than carrot juice.

Non Falsifiable-

Aloe vera gel is the best  natural skin moisturizer.

Aloe vera gel can heal  wounds by boosting  cell renewal.

Drinking aloe juice can  reduce the risk of lung  cancer.

7 0
3 years ago
You jump off a truck and accelerate toward the surface of the Earth. Does the Earth accelerate toward you?
Triss [41]

When we jump from the truck and accelerate towards the earth surface, the earth also accelerates towards us but it's acceleration is very negligible.

To find the answer, we need to know about the acceleration of earth due to the gravitational attraction.

<h3>What's the gravitational force between the earth and a person?</h3>
  • Gravitational attraction force is GMm/r² between the earth and a person.
  • M= mass of the earth

m= mass of the person

r= separation between them.

<h3>What's the acceleration of the earth towards the person when he jumps from a truck?</h3>
  • According to Newton's second law, Force = M×acceleration
  • Acceleration= Force / M
  • Here, Force = GMm/r²,

so acceleration of earth= Gm/r²

  • As this acceleration is very small, so we can't notice it.

Thus, we can conclude that the earth also accelerates towards us.

Learn more about the gravitational force here:

brainly.com/question/72250

#SPJ4

7 0
1 year ago
To have the highest magnification in a telescope, the focal length of the objective lens should be _________ and the focal lengt
Darina [25.2K]

Answer:

Large; small.

Explanation:

A telescope can be defined as an optical instrument or device which comprises of a curved mirror and lenses used for viewing distant objects i.e objects that are very far away such as stars and other planetary bodies. The first telescope was invented by Sir Isaac Newton.

To have the highest magnification in a telescope, the focal length of the objective lens should be large and the focal length of the eyepiece lens should be small.

This ultimately implies that, the eyepiece lens has a small focal length while the objective lens has a large focal length.

6 0
2 years ago
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