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3 years ago

Please please please help me

Physics

1 answer:

pogonyaev3 years ago

3 0

Answer:

C) seems to be the correct one

Each alpha particle emitted decreases the mass of the nucleus by 4 and decreases the atomic number by 2.

Also, each beta particle will increase the atomic number by 1.

So if C emits 5 alpha particles the atomic mass decreases by 20 and the atomic number decreases by 10. Then emission of 2 beta particles brings the atomic number up to minus 8.

So a total of 7 particles have been emitted and the number of alpha particles emitted exceeds the number of beta particles emitted.

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A ball attached to a string is whirled around in a horizontal circle having a radius r. If the radius of the circle is changed t

LenKa [72]

Answer:

Option D: Four times the original speed.

Explanation:

A centripetal force accelerates a body by changing the direction of the body's velocity without changing the body's speed.

The speed(v) is therefore constant, thereby making the magnitudes of the of the acceleration and the force constant.

The formula used to calculate the Centripetal force is given below:

$F = \frac{mv^2}{r}$

where F represents the Centripetal force, m represents the mass of the moving body, v represents the speed or velocity at which the body is moving and r represents the radius.

Making the speed the subject of the formula: $v^{2} = \frac{rF}{m} \\$

Therefore, when the radius (r) is changed to 4r, i.e r = 4r

speed(v) becomes $v^2 = \frac{4rF}{m}$

After comparing, the difference between the speeds is Four times the original speed.

5 0

3 years ago

It has been a hot summer, so when you arrive at a lake, you decide to go for a swim even though it it nighttime. The water is co

nikitadnepr [17]

Answer:

(d) Water has a high specific heat.

Explanation:

At night, when the temperature of earth goes down due to loss of heat , the temperature of water is lost slowly and temperature of land is lost fast because of high specific heat of water . Water loses as well as gains temperature comparatively slowly due to its high specific heat .

During daytime when earth gains heat , the temperature of land rises more rapidly than water so water appears cool even during daytime when land becomes hotter . It is also due to high heat holding capacity of water or due to high specific heat of water .

8 0

3 years ago

Which statement describes how nuclear power generation systems work?

galben [10]

Answer:

c- heat for electricity generation process comes from nuclear fission

Explanation:

nuclear fission is splitting of atoms to release energy held at nucleus of atoms

4 0

2 years ago

Helpppppppp<br> ill give brainliest

Nina [5.8K]

Answer:

I believe the answer is

$B. \: 3 \: red, \: 8 \: yellow, \: 1 \: blue$

Explanation:

I may be incorrect because I used to do this a long time ago but I believe I am correct

HOPE THIS HELPS!

4 0

3 years ago

A hockey puck on a frozen pond is given an initial speed of 20.0 m/s. If the puck always remains on the ice and slides 115 m bef

bekas [8.4K]

Answer:

μ_k = 0.1773

Explanation:

We are given;

Initial velocity;u = 20 m/s

Final velocity;v = 0 m/s (since it comes to rest)

Distance before coming to rest;s = 115 m

Let's find the acceleration using Newton's second law of motion;

v² = u² + 2as

Making a the subject, we have;

a = (v² - u²)/2s

Plugging relevant values;

a = (0² - 20²)/(2 × 115)

a = -400/230

a = -1.739 m/s²

From the question, the only force acting on the puck in the x direction is the force of friction. Since friction always opposes motion, we see that:

F_k = −ma - - - (1)

We also know that F_k is defined by;

F_k = μ_k•N

Where;

μ_k is coefficient of kinetic friction

N is normal force which is (mg)

Since gravity acts in the negative direction, the normal force will be positive.

Thus;

F_k = μ_k•mg - - - (2)

where g is acceleration due to gravity.

Thus,equating equation 1 and 2,we have;

−ma = μ_k•mg

m will cancel out to give;

-a = μ_k•g

μ_k = -a/g

g has a constant value of 9.81 m/s², so;

μ_k = - (-1.739/9.81)

μ_k = 0.1773

3 0

3 years ago