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3 years ago

Describe how to determine the number of electrons using the Periodic Table of the Elements

Physics

1 answer:

Paladinen [302]3 years ago

3 0

Answer:

Explanation: The periodic table contains rows and columns. To find how many valence electrons are in an element, simply locate the column number that it is in, and that determines the number of valence electrons in an element. This rule works only for elements excluding the transition metals

Explanation:

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A 0.50-kg ball, attached to the end of a horizontal cord, is rotated in a circle of radius 1.9 m on a frictionless horizontal su

Sedaia [141]

Answer:

$\boxed {\boxed {\sf 18 \ m/s}}$

Explanation:

The ball is moving in a circle, so the force is centripetal.

One formula for calculating centripetal force is:

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

The mass of the ball is 0.5 kilograms. The radius is 1.9 meters. The centripetal force is 85 Newtons or 85 kg*m/s².

$F_c$ = 85 kg*m/s²
m= 0.5 kg
r= 1.9 m

Substitute the values into the formula.

$85 \ kg*m/s^2 = \frac{0.5 \ kg *v^2}{1.9 \ m}$

Isolate the variable v. First, multiply both sides by 1.9 meters.

$(1.9 \ m)(85 \ kg*m/s^2) = \frac{0.5 \ kg *v^2}{1.9 \ m}*1.9 \ m$

$(1.9 \ m)(85 \ kg*m/s^2) = {0.5 \ kg *v^2}$

$161.5 \ kg*m^2/s^2 = 0.5 \ kg*v^2$

Divide both sides by 0.5 kilograms.

$\frac {161.5 \ kg*m^2/s^2}{0.5 \ kg} = \frac{0.5 \ kg*v^2}{0.5 \ kg}$

$\frac {161.5 \ kg*m^2/s^2}{0.5 \ kg} =v^2$

$323 \ m^2/s^2 = v^2$

Take the square root of both sides of the equation.

$\sqrt {323 \ m^2/s^2} =\sqrt{ v^2$

$\sqrt {323 \ m^2/s^2} =v$

$17.9722007556 \ m/s =v$

The original measurements have 2 significant figures, so our answer must have the same.

For the number we found, 2 sig fig is the ones place. The 9 in the tenth place tells us to round the 7 to an 8.

$18 \ m/s =v$

The maximum speed is approximately 18 meters per second.

8 0

3 years ago

Track and field is an individual sport. True or False?

mars1129 [50]

Most events in track and field are individual except relay races. Therefore, it would probably be true.

7 0

3 years ago

Read 2 more answers

a motorcyclist starts from rest and accelerates at rate of 4 meters per second squared north. what is the final velocity of the

MArishka [77]

Answer:

80m/s

Explanation:

Final velocity is given by

v=u+at

when a motorcyclist starts from rest, initial velocity (u) =0

therefore

v=0+4*20

v=80m/s

that's the answer

8 0

4 years ago

Three capacitors with individual capacitances of 2 μF, 5 μF, and 10 μF

rodikova [14]

Answer:

1.25C

Explanation:

When capacitance is in series we add them like this: 1/Ctotal = 1/C1 +1/C2 + 1/C3.....

1/C = 1/2 + 1/5 + 1/10 = 5 + 2 + 1/10 = 8/10

C = 10/8 = 1.25

Capacitance = Charge/potential difference(Q/V)

1.25 = Charge/12

Total charge = 1.25 ×12 =15coulombs

5 0

3 years ago

A 0.30 kg yo-yo consists of two solid disks of radius 5.10 cm joined together by a massless rod of radius 1.0 cm and a string wr

docker41 [41]

Answer:

0.70046 m/s²

2.732862 N

Explanation:

g = Acceleration due to gravity = 9.81 m/s²

m = Mass of yo-yo = 0.3 kg

R = Radius of rolling disk = 5.1 cm

r = Radius of rod = 1 cm

For a rolling disks the acceleration is given by

$a=\frac{g}{1+\frac{R^2}{2r}}\\\Rightarrow a=\frac{9.81}{1+\frac{0.051^2}{2\times 0.01^2}}\\\Rightarrow a=0.70046\ m/s^2$

The acceleration of the yo-yo is 0.70046 m/s²

The tension in the string will be

$T=m(g-a)\\\Rightarrow T=0.3\times (9.81-0.70046)\\\Rightarrow T=2.732862\ N$

The tension in the string is 2.732862 N

8 0

3 years ago