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3 years ago

The mass of a body on the surface of the earth is 12kg. If acceleration due to gravity on

1 answer:

4 0

The mass is still 12kg. Mass is the amount of matter, so that is independent of gravity. However, weight differs. Weight of this object on earth would be 117.6 N and 19.6 N on the moon.

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While operating a vehicle on any highway of this state, it is illegal to physically hold or support a wireless device with any p

algol13

Answer:

True

Explanation:

In Massachusetts it's illegal to drive while texting or on your phone.

3 0

4 years ago

was an American writer, poet, editor, and literary critic. Poe is best known for his poetry and short stories

Art [367]

Answer:

poet

Explanation:

4 0

3 years ago

Aconstant current of 3 Afor 4 hours is required to charge an automotive battery. If the terminal voltage is V, where t is in hou

kirza4 [7]

Answer:

(a) 43.2 kC

(b) 0.012V kWh

(c) 0.108V cents

Explanation:

<u>Given:</u>

i = current flow = 3 A
t = time interval for which the current flow = $4\ h = 4\times 3600\ s = 14400\ s$
V = terminal voltage of the battery
R = rate of energy = 9 cents/kWh

<u>Assume:</u>

Q = charge transported as a result of charging
E = energy expended
C = cost of charging

Part (a):

We know that the charge flow rate is the electric current flow through a wire.

$\therefore i = \dfrac{Q}{t}\\\Rightarrow Q =it\\\Rightarrow Q = 3\times 14400\\\Rightarrow Q = 43200\ C\\\Rightarrow Q = 43.200\ kC\\$

Hence, 43.2 kC of charge is transported as a result of charging.

Part (b):

We know the electrical energy dissipated due to current flow across a voltage drop for a time interval is given by:

$E = Vit\\\Rightarrow E = V\times 3\times 4\\\Rightarrow E = 12V\ Wh\\\Rightarrow E = 0.012V\ kWh\\$

Hence, 0.012V kWh is expended in charging the battery.

Part (c):

We know that the energy cost is equal to the product of energy expended and the rate of energy.

$\therefore \textrm{Cost}=\textrm{Energy}\times \textrm{Rate}\\\Rightarrow C = ER\\\Rightarrow C = 0.012V\times 9\\\Rightarrow C =0.108V\ cents$

Hence, 0.108V cents is the charging cost of the battery.

4 0

4 years ago

Select the phrases that correctly describe density. Select one or more: a. Density is a physical property. b. Density determines

Serga [27]

Answer:

Options (A), (B), (D), and (E).

Explanation:

Density is a physical property that describes the relationship between mass and volume. This property shows whether an object will float or it will get sink. The density of substances changes with the changing temperature, as both are inversely proportional to each other.

Mathematically, density can be written as,

Density = $\frac{mass}{volume}$

ρ = $\frac{m}{v}$ , Where, ρ = density, m = mass, v = volume

Thus, the correct answers are options (A), (B), (D), and (E).

6 0

3 years ago

An open container holds ice of mass 0.500 kgkg at a temperature of -17.4 âCâC . The mass of the container can be ignored. Heat i

MaRussiya [10]

Answer:

a) t = 235.2minute

b) 260.94minutes

Explanation:

Heat energy is defined as the energy required to change the temperature of a substance by 1kelvin.

It is expressed as H = mc∆t where m is the mass of the water

c is the specific heat capacity of the water/ice

∆t is the change in temperature

Total heat required to melt the ice

H = mLice + mc∆t

Lice is the latent heat of fusion of ice

a) To calculate how much time tmelts passes before the ice starts to melt, we will only calculate heat energy absorb by the ice before it melts.

H = mLice

H = 0.50(334000)

H = 167,000Joules

If heat is supplied to the container at the constant rate of 710 J/minute, the time taken before the ice starts to melt will be:

t = 167,000/710

t = 235.2minutes

b) To calculate how much time trise does it take before the temperature begins to rise above 0°C, we will calculate the total energy absorbed at 0°C first.

H = 0.50(334000) + 0.50(2100)(0-(-17.4)

Note that the ice melts at 0°C which will be the final temperature

H = 167,000+18270

H = 185,270oules

Since heat is supplied to the container at the constant rate of 710 J/minute

710Joules = 1minute

185,270Joules= x

x = 185,270/710

x = 260.94minutes

The time taken before the temperature begins to rise is 260.94minutes:

6 0

3 years ago

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