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allochka39001 [22]
3 years ago
12

Radon has a half-life of 56s. After what time will it's activity be reduced to (a) 90% (b) 50% (c) 10% of it's initial value​

Physics
1 answer:
guapka [62]3 years ago
6 0

Answer:

A) 11.2 s

B) is 56 s

C) 170.8 s

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Encuentra la masa molar<br><br> TO<br><br> de 65 litros de SO2
shepuryov [24]

La masa molar de 65 litros de SO2 es igual a 64,1 g/mol.

<h3>Masa molar</h3>

La masa molar de un compuesto depende de su masa presente en 1 mol, entonces:

                                          MM=\frac{m}{mol}

Para calcular la masa molar de un compuesto, simplemente suma las masas de cada elemento en el compuesto, así:

MM_O = 16g/mol\\MM_S= 32.1g/mol

                                32.1 + 2\times 16 = 64.1g/mol

Así, la masa molar de 65 litros de SO2 es igual a 64,1 g/mol.

Obtenga más información sobre la masa molar en: brainly.com/question/17109809

8 0
3 years ago
7. Two people are pushing a 40.0kg table across the floor. Person 1 pushes with a force of 490N
artcher [175]

Answer:

20.4 m/s^{2}

Explanation:

To start doing this problem, first draw a free body diagram of the table. My teacher always tells us to do this, and I find that it is very helpful. I have attached a free body diagram to this answer- take a look at it.

First, let us see if Net force = MA. To do that, we need to determine whether the object is at equilibrium horizontally. For an object to be at equilibrium, it either needs to be moving at a constant velocity or not moving at all. Also, if an object is at equilibrium, there will not be any acceleration. But we know that there IS acceleration horizontally, so it cannot be in equilibrium. If it is not in equilibrium, we can use the formula ∑F= ma.

Let us determine the net force. Since the object is moving horizontally, we can ignore the weight and normal force, because they are vertical forces. The only horizontal forces we need to worry about are the applied force and force of friction.

Applied force = 1055 N (490 + 565)

Friction force= Unknown

To find the friction force, use the kinetic friction formula, Friction = μkN

μk is the coefficient, which the problem includes- it is 0.613.

N is the normal force, which we have to find.

*To find the normal force, we have to determine if the object is at equilibrium VERTICALLY. Since it has no acceleration vertically (it's not moving up/down), it is at equilibrium. Now, when an object is at equilibrium in one direction, it means that all the forces in that direction are equal. What are our vertical forces? Weight (mg) and Normal force (N). So it means that the Normal force is equal to the Weight.

Weight = mg = (40)(9.8) = 392 N

Normal force = 392 N

Now, plug it back into the formula (μkN): (0.613)(392) = 240.296 N

Friction = 240.296 N

Now that we know the friction, we can find the horizontal net force. Just subtract the friction force, 240.296 from the applied force, 1055 N

Horizontal Net Force: 814.704 N

Now that we know the net force, plug in the numbers for the formula

∑F= ma.

814.704 = (40.0)(a)

*Divide on both sides)

a = 20.3676 m/s^2

Round it to 3 significant figures, to get:

20.4 m/s^{2}

7 0
3 years ago
How does the force of gravity exerted
givi [52]

The two forces of gravity are equal

Explanation:

We can answer this question by applying Newton's third law of motion, which states that:

"When an object A exerts a force (called action) on an object B, then object B exerts an equal and opposite force (called reaction) on object A"

In this problem, we can identify the Sun as object A and the Earth as object B. This means that the force of gravity exerted by the Sun on the Earth is the action, while the force of gravity exerted by the Earth on the Sun is the reaction: according to Newton's third law, these two forces are equal and opposite.

Therefore, the two forces of gravity are equal in magnitude, which is given by:

F=\frac{GMm}{r^2}

where

G is the gravitational constant

M is the mass of the Sun

m is the mass of the Earth

r is the separation between the Earth and the Sun

Learn more about Newton's third law:

brainly.com/question/11411375

#LearnwithBrainly

8 0
3 years ago
Which of the following is a chemical change?
e-lub [12.9K]
A screw driver rusting when left in a pail of water is a chemical reaction
4 0
3 years ago
Read 2 more answers
I NEED HELP ITS AN ECON QUESTION THE PICTURE IS ABOVE IF YOUR CORRECT I WILL GIVE YOU THE EXTRA POINTS APPRECIATE THE HELP
tester [92]

Answer:

choose to spend limited resources to meet their needs

3 0
3 years ago
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