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3 years ago

10 points

Physics

1 answer:

zysi [14]3 years ago

3 0

Answer: inside nucleus= 84 outside nucleus= 36

Explanation:

Recall that an atom is made up of three subatomic particles named protons, neutrons and electrons. The proton and neutrons are found inside the nucleus while electrons are found outside the atom nucleus.

So, given that:

Atomic number of krypton = 36

Mass number of krypton = 84

The number of protons = 36 (same as atomic number)

The number of neutrons = (Mass number - Number of protons) 84 - 36 = 48

Thus, particles inside nucleus = (protons + neutrons) = 84

While particles (electrons) outside nucleus = 36 (same as the atomic number which is 36).

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What did early South American civilization do to promote farming

aliya0001 [1]

The Incan used there many techniques to more efficiently use water.

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3 years ago

A skydiver falls toward the ground at a constant velocity. Which statement best applies Newton’s laws of motion to explain the s

Tema [17]

Answer:

The answer is (a.) An upward force balances the downward force gravity on the skydiver

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7 0

3 years ago

Read 2 more answers

If the mass of the ladder is 12.0 kgkg, the mass of the painter is 55.0 kgkg, and the ladder begins to slip at its base when her

Marysya12 [62]

Answer:

μ = 0.336

Explanation:

We will work on this exercise with the expressions of transactional and rotational equilibrium.

Let's start with rotational balance, for this we set a reference system at the top of the ladder, where it touches the wall and we will assign as positive the anti-clockwise direction of rotation

fr L sin θ - W L / 2 cos θ - W_painter 0.3 L cos θ = 0

fr sin θ - cos θ (W / 2 + 0,3 W_painter) = 0

fr = cotan θ (W / 2 + 0,3 W_painter)

Now let's write the equilibrium translation equation

X axis

F1 - fr = 0

F1 = fr

the friction force has the expression

fr = μ N

Y Axis

N - W - W_painter = 0

N = W + W_painter

we substitute

fr = μ (W + W_painter)

we substitute in the endowment equilibrium equation

μ (W + W_painter) = cotan θ (W / 2 + 0,3 W_painter)

μ = cotan θ (W / 2 + 0,3 W_painter) / (W + W_painter)

we substitute the values they give

μ = cotan θ (12/2 + 0.3 55) / (12 + 55)

μ = cotan θ (22.5 / 67)

μ = cotan tea (0.336)

To finish the problem, we must indicate the angle of the staircase or catcher data to find the angle, if we assume that the angle is tea = 45

cotan 45 = 1 / tan 45 = 1

the result is

μ = 0.336

5 0

4 years ago

According to the formula for stopping distance, how many feet will it take you to stop, from 60 mph?

myrzilka [38]

Answer:

534 ft

Explanation:

given,

speed of the vehicle = 60 mph

1 mph = 0.447 m/s

60 mph = 60 x 0.447 = 26.82 m/s

stopping distance = ?

Stopping distance of the car is equal to the distance traveled in the reaction time and the braking distance.

Reaction time of a common person = 1.5 s

taking coefficient of friction of the road = 0.3

using equation of stopping sight distance

S.D = RD + BD

RD is Reaction distance

RD = v t_r

RD = 26.82 x 1.5

RD = 40.23 m

BD is the braking distance

$BD = \dfrac{v^2}{2\mu g}$

$BD = \dfrac{26.82^2}{2\times 0.3\times 9.8}$

BD = 122.33 m

Stopping sight distance

SD = 40.23 + 122.33

SD = 162.56 m

1 m = 3.28 ft

162.56 m = 162.56 x 3.28

= 533.20 ft ≈ 534 ft

hence, the stopping distance will be equal to 534 ft

8 0

3 years ago

Mechanical energy that has been ‘lost' to friction isn't really lost. It just is no longer in its mechanical form. True or False

Vadim26 [7]

Answer:

True.

Explanation:

Energy can be defined as the ability (capacity) to do work. The two (2) main types of energy are;

a. Gravitational potential energy (GPE): it is an energy possessed by an object or body due to its position above the earth.

b. Kinetic energy (KE): it is an energy possessed by an object or body due to its motion.

Furthermore, the mechanical energy of a physical object or body is the sum of the potential energy and kinetic energy possessed by the object or body.

Mathematically, it is given by the formula;

Mechanical energy = G.P.E + K.E

Mechanical energy that has been ‘lost' to friction isn't really lost. It just is no longer in its mechanical form. This is ultimately in accordance with the law of conservation of energy, which states that energy cannot be destroyed but can only be converted or transformed from one form to another.

Hence, Mechanical energy that has been ‘lost' to friction isn't really lost but converted into heat energy.

4 0

3 years ago