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Kaylis [27]
3 years ago
10

True or false: Black holes are invisible because they do not reflect light? A. true B. false

Physics
1 answer:
BaLLatris [955]3 years ago
3 0
True, because they have very strong gravitational field that even the light -the fastest thing known- can’t escape its power
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What do you think happened to the energy you transferred to the notebook when you pushed it?
xeze [42]

Answer:

It got transferred to kinetic energy

Explanation:

8 0
3 years ago
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Which of the following is a contact force?
3241004551 [841]

Answer:

b friction

Explanation:

Contact forces

Contact forces are forces that act between two objects that are physically touching each other. Examples of contact forces include:

Reaction force

An object at rest on a surface experiences reaction force. For example, a book on a table.

A box rests on a table. There are two arrows, equal in size but going in opposite directions, up and down, from the point where the box meets the table.

Tension

An object that is being stretched experiences a tension force. For example, a cable holding a ceiling lamp.

A box hangs from a rope. Two arrows which are equal in size act upwards and dowards from the top and bottom of the rope.

Friction

Two objects sliding past each other experience friction forces. For example, a box sliding down a slope.

A box rests on an incline. There are three arrows; one acting vertically downwards from the centre of the box’s base. One arrow acts perpendicular to the incline. One arrow acts up the incline.

Air resistance

An object moving through the air experiences air resistance. For example, a skydiver falling through the air.

A box falls from the sky. Two arrows, equal in size and opposite in direction act upwards from the box and downwards from the box

When a contact force acts between two objects, both objects experience the same size force, but in opposite directions. This is Newton's Third Law of Motion.

3 0
3 years ago
An emf of 0.50 v is induced across a coil when the current through it changes uniformly from 0.55 to 0.95 a in 0.40 s. what is t
love history [14]

The correct answer is 0.67 h

The coil's induced emf is specified as e=0. 50 v.

i i = 0.55 A is the initial value of the current flow.

I f = 0.95 A is the total amount of current flowing.

The shift in current occurs in a period of time when dt = 0.40 s.

The self-inductance is determined as follows:

The current change rate is represented here by dI/dt.

Step 2 After entering the values,

As a result, the self-inductance is 0.67 H.

The definition of self inductance is the induction of a voltage in a wire that carries current when the current in the wire is changing. When there is self-inductance, a circuit's own changing current creates a magnetic field that causes a voltage to be induced.

Learn more about Self inductance here :-

brainly.com/question/15293029

#SPJ4

6 0
1 year ago
Light year is a unit of?
IrinaVladis [17]
Light year is the unit of distance. It is the distance that an object travels in one year with the speed of light.

In short, Your Answer would be "Distance"

Hope this helps!
3 0
3 years ago
Benny wants to estimate the mean lifetime of Energizer batteries, with a confidence level of 97%, and with a margin of error not
VikaD [51]

Answer:

143 batteries does Benny need to sample

Explanation:

Given data

confidence level = 97%

error  = ±10 hours

standard deviation SD = 55 hours

to find out

how many batteries does Benny need to sample

solution

confidence level is 97%

so a will be 1 - 0.97 = 0.03

the value of Z will be for a 0.03 is 2.17 from standard table

so now we calculate no of sample i.e

no of sample  = (Z× SD/ error)²

no of sample = (2.16 × 55 / 10)²

no of sample = 142.44

so  143 batteries does Benny need to sample

7 0
3 years ago
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