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3 years ago

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Two identical small charged spheres are a certain distance apart, and each initially experiences an electrostatic force of magni

tude F due to the other. With time, charge gradually diminishes on both spheres. When each of the spheres has lost half its initial charge, the magnitude of the electrostatic force will be
a) 1/16 F
b) 1/8 F
c) 1/2 F
d) 1/4 F

1 answer:

sweet-ann [11.9K]3 years ago

5 0

Answer:

d) 1/4 F

Explanation:

The magnitude of electrostatic force between stationary charges is described by Coulomb's law. This law states that this force is proportional to the magnitudes of the charges:

$F\propto q_1q_2$

When each of the spheres has lost half its initial charge, we have:

$q_1'=\frac{q_1}{2}\\q_2'=\frac{q_2}{2}$

So, the new electrostatic force is:

$F'\propto q_1'q_2'\\F'\propto \frac{q_1}{2}\frac{q_2}{2}\\F'\propto \frac{q_1q_2}{4}\\F'\propto\frac{1}{4}F$

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A 300 g glass thermometer initially at 23 ◦C is put into 236 cm3 of hot water at 87 ◦C. Find the final temperature of the thermo

DIA [1.3K]

Answer:

$74^{\circ} C$

Explanation:

We are given that

Mass of glass, $m=300 g$

$T_1=23^{\circ}$

Volume, $V=236cm^3$

Mass of water= $density\times volume=1\times 236=236 g$

Density of water= $1g/cm^3$

Temperature of hot water, $T=87^{\circ}$

Specific heat of glass, $C_g=0.2cal/g^{\circ}C$

Specific heat of water, $C_w=1 cal/g^{\circ}C$

$Q_{glass}=m_gC_g(T_f-T_1)=300\times 0.2(T_f-23)$

$Q_{water}=m_wC_w(T_f-T)=236\times 1(T_f-87)$

$Q_{glass}+Q_{water}=0$

$300\times 0.2(T_f-23)+236\times 1(T_f-87)$

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$296T_f=20532+1380=21912$

$T_f=\frac{21912}{296}=74^{\circ} C$

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2 years ago

Characteristics that a scientific measuring tool should have

bixtya [17]

Answer:

RELIBILITY - is the consistency of your measurement, or the degree to which an

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same subjects. In short, it is the repeatability of your measurement. A measure is considered

reliable if a person's score on the same test given twice is similar. It is important to

remember that reliability is not measured, it is estimated. A good instrument will produce

consistent scores. An instrument’s reliability is estimated using a correlation coefficient of

one type or another.

VALIDITY

VALIDITY - Validity is the extent to which a test measures what it claims to measure. It is

vital for a test to be valid in order for the results to be accurately applied and interpreted.

Validity isn’t determined by a single statistic, but by a body of research that demonstrates

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truth or falsity of a given inference, proposition or conclusion."

PRACTICIBILITY

PRACTICIBILITY - It should be feasible & usable. Quality of being usable in context to the

objective to be achieved.

USABILITY

USABILITY(practicality) ease in administration, scoring, interpretation and application, low

cost, proper mechanical make – up

MEASUREABILITY

MEASUREABILITY - It should measure the objective to be achieved.

Explanation:

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2 years ago

A force of 40N is applied to a 28 g mass, what is the acceleration? (round to the hundredths place)

Leno4ka [110]

Answer:

1428.6m/s²

Explanation:

Given parameters:

Force applied on the body = 40N

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1000g = 1kg

28g will therefore be 0.028kg

Unknown:

Acceleration = ?

Solution:

To solve this problem, we use the expression derived from Newton's second law of motion.

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3 years ago

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lapo4ka [179]

Answer:

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When the springs are connected end to end, it means they are connected in series. When the springs are connected in series, the stress applied to the system gets applied to each of the springs without any change in magnitude while the strain of the system is the sum total of strains of each spring. The spring constant of the resultant system is given as,

$\frac{1}{K_{system}} = (\frac{1}{K_{1}})+(\frac{1}{K_{2}})+(\frac{1}{K_{3}})+ (\frac{1}{K_{4}})+.....+(\frac{1}{K_{n}})$

Here, n = 10

Spring constant of each spring = k

Thus,

$\frac{1}{K_{system}} = (\frac{1}{K_{1}})+(\frac{1}{K_{2}})+(\frac{1}{K_{3}})+ (\frac{1}{K_{4}})+.....+(\frac{1}{K_{10}})$

$\frac{1}{K_{system}} = (\frac{1}{k})+(\frac{1}{k})+(\frac{1}{k})+(\frac{1}{k})+(\frac{1}{k})+(\frac{1}{k})+(\frac{1}{k})+(\frac{1}{k})+(\frac{1}{k})+(\frac{1}{k})$

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3 years ago

Read 2 more answers

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Mamont248 [21]

Answer:

1. 571.43m/s

2. 142.9m and 342.9m

Explanation:

1.Take the difference in time.

1.2-0.7=0.7 seconds

Take the distance between them and divide with differnce in time.

400÷0.7=571.43 seconds.

2.Take the time of the two men and divide by two.

0.5÷2= 0.25 secs

1.2÷2= 0.6 secs

multiply each with the velocity.

0.25×571.43=142.9m

0.6×571.43=342.9m

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1 year ago