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3 years ago

If the voltage impressed across a circuit is held constant while the resistance is halved, what change occur?

Physics

1 answer:

egoroff_w [7]3 years ago

3 0

Answer:

The current doubles

Explanation:

In a circuit, Ohm's law gives the relationship between voltage, current and resistance:

$V=RI$

where

V is the voltage

R is the resistance

I is the current

In this problem,

V is held constant

R is halved: $R'=\frac{R}{2}$

Therefore, the new current is

$I'=\frac{V}{R'}=\frac{V}{R/2}=2\frac{V}{R}=2I$

So, the current doubles.

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True or False. Recent findings lend strong support to the theory that a black hole lies at the center of the Milky Way and of ma

Genrish500 [490]

Answer:

True

Explanation:

In 2019 was taken the first image of a supermassive black hole in the center of the galaxy M87 with the Event Horizon Telescope, which is a network of radio telescope located in different points of the Earth, with the purpose of making a telescope of the size of the Earth.

A radio telescope is an antenna that is capable to perceive the light in the radio part of the electromagnetic spectrum¹.

It is important to notice that in the picture what it can be seen is the effect that the black hole has in the nearby stars.

Key terms:

¹Electromagnetic spectrum: decomposition of light in its different wavelengths (from radio waves to gamma rays).

7 0

3 years ago

If a spear is jabbeb exactly at that place where the fish appears in water, the fish is not killed

Korvikt [17]

You have learned your lesson well, Suhay. Your statement is correct.

The light rays from the fish BEND when they flow out of the water into the air. But our primitive brain still believes that the light rays flow STRAIGHT from the fish. The result is that the fish does not APPEAR to be at that place where it really is.

7 0

3 years ago

A gang of robbers is escaping across city roofs at night. They come to the edge of one building and need to drop down to their g

REY [17]

Answer:

a) They will hit the ground with a speed of 19.6 m/s.

b) They are at a height of 20 m.

c) It is not a safe jump.

Explanation:

Hi there!

a) The equations of height and velocity in function of time of a free falling body are the following:

h = h0 + v0 · t + 1/2 · g · t²

v = v0 + g · t

Where:

h = height of the object at time t.

h0 = initial height.

v0 = initial velocity.

t = time.

g = acceleration due to gravity (-9.8 m/s² considering downward as negative direction).

v = velocity of the object at time t.

Using the equation of velocity, let's find the velocity at which they will hit the ground. The pebble is dropped (initial velocity = 0) and it takes 2 s to reach the ground:

v = v0 + g · t (v0 = 0)

v = g · t

v = -9.8 m/s² · 2.0 s

v = -19.6 m/s

They will hit the ground with a speed of 19.6 m/s.

b)Now, we have to use the equation of height:

h = h0 + v0 · t + 1/2 · g · t²

If we place the origin of the frame of reference on the ground, we have to find the initial height (h0) knowing that at t = 2.0 s, h = 0 m

0 m = h0 - 1/2 · 9.8 m/s² · (2.0 s)²

h0 = 1/2 · 9.8 m/s² · (2.0 s)²

h0 = 20 m

They are at a height of 20 m.

c)According to a NASA paper (Issues on Human Acceleration Tolerance After Long-Duration Space Flights, figure 10), if you fall with a vertical velocity greater than 17 m/s it is unlikely that you will survive. So, it is not a safe jump.

3 0

3 years ago

A teacher asks her students to jump off of the ground. Once the students complete the task, she says, "All of you just made Eart

Crazy boy [7]

Answer:

Explained below

Explanation:

A) Newton's first law of motion states that an object will remain at rest or continue in its current state of motion except it is acted upon by another force.

Now using this law, when you jump off the ground, the earth will move a tiny bit and accelerate due to the force applied by the jumping.

B) Newton's 2nd law states that the acceleration of a system is directly proportional to the net external force acting on that system, is in the same direction with it and also inversely proportional to the mass.

In this case, when one jumps, an external force is exerted on the earth and we are told it is directly proportional to the acceleration of the system which in this case it's the earth, then it means that there is some motion by the earth even though you didn't see it move.

C) Newton's third law of motion states that to every action, there is an equal and opposite reaction.

In this case the motion of the jumper will lead to an equal and opposite reaction of the earth.

8 0

2 years ago

How do you find the average speed of an object?

Aleonysh [2.5K]

Answer:

Average speed is total distance divided by total time.

v = d / t

5 0

3 years ago

Read 2 more answers