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dolphi86 [110]
3 years ago
7

A book starts on a shelf 1 m off of the ground. You then move the book to a higher shelf that is 3 m off of the ground. If the s

ystem gained 20 J of gravitational potential energy, what is the mass of the book?
Physics
1 answer:
JulsSmile [24]3 years ago
4 0

Answer:

Using g = 9.8: 1.02 kg, Using g = 10: 1 kg

Explanation:

E = mgh

20 = m(9.8)(3 - 1)

20 = 9.8m(2)

20 = 19.6m

m = 1.02 kg

I'm now assuming you may be using a g constant of 10, thus the close integer result, in which case the mass would be exactly 1 kilogram.

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You observe that a negatively charged plastic pen repels a chargedpiece of magic tape. You then observe that the same piece of t
swat32

According to the statement there is a force of repulsion between the two objects. Remember that two objects must have the same charge so that they repel each other. In this way if the tape is repelled by a plastic pen that is negatively charged, this allows us to appreciate that the tape is also negatively charged. Now if the tape repels the sphere, therefore the sphere is also negatively charged.

Under these considerations the correct answers would be

2. Sodium ions from the salt water on your hand moved onto the sphere

4. The excess negative charge from the sphere spread out all over your body

6. Electrons from the sphere moved into the salt water on your skin, where they reacted with sodium ions

7. After you touched it, the metal sphere was very nearly neutral.

3 0
3 years ago
A car stops with an acceleration of -20 m/s/s in 8 seconds. How far did it go while stopping?
Sophie [7]

Answer:

640 m.

Explanation:

The following data were obtained from the question:

Acceleration (a) = –20 m/s/s

Time (t) = 8 s

Final velocity (v) = 0 m/s

Distance (s) =.?

Next, we shall determine the initial velocity (u) of the car. This can be obtained as follow:

Acceleration (a) = –20 m/s/s

Time (t) = 8 s

Final velocity (v) = 0 m/s

Initial velocity (u)

a = (v – u) / t

–20 = (0 – u) / 8

–20 = – u / 8

Cross multiply

–20 × 8 = – u

– 160 = – u

Divide both side by – 1

u = – 160 / – 1

u = 160 m/s

Finally, we shall determine the distance travelled by the car before stopping as follow:

Time (t) = 8 s

Final velocity (v) = 0 m/s

Initial velocity (u) = 160 m/s

Distance (s) =.?

s = (v + u)t /2

s = (0 + 160) × 8 /2

s = (160 × 8) /2

s = 1280 / 2

s = 640 m

Therefore, the car travelled 640 m before stopping.

3 0
4 years ago
!!!!!!!!!URGENT!!!!!!!!!!!!!! Physical Science lesson 6 unit 2 I need the answers ASAP thanks in advance
andrezito [222]
I can only answer questions 1-3 sorry :\
1. d
2. c
3. b
hopefully that helps! :)
6 0
3 years ago
Read 2 more answers
An eraser is thrown upward with an initial velocity of 5.0 m/s. The eraser's velocity after 7.0 seconds is ____ m/s.
Vedmedyk [2.9K]

Given parameters:

Initial velocity of eraser  = 5.0m/s

Time  = 7.0s

Unknown:

Final velocity = ?

Solution:

Since we have been given the initial velocity and duration of the throw, we can apply the appropriate motion equation to solve this problem.

       V  = U - 2gt

where V is the final velocity

            U is the initial velocity

             g is the acceleration due to gravity = 9.8m/s²

            t is the time taken

       V  = U - gt

       V = 5 - (9.8)(7)

       V = -63.6 or -64m/s

The velocity is -64m/s

   

3 0
3 years ago
Where is information first stored in a human brain​
Dmitrij [34]

Answer:

The long-term memories are stored throughout the brain as groups of neurons, the brain stores memories in three ways--Short-term memories, Sensory memory and Long-term memory the human brain cell can hold 5 times as much of information as the Encyclopedia Britannica.

Explanation:

I hope this helps, I got this from a website called Stack Exchange :)

7 0
3 years ago
Read 2 more answers
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