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3 years ago

When an electron falls from a higher energy level to a lower energy level how is the energy released?

1 answer:

5 0

When a valence electron absorbs energy in the form of heat or light it uses that energy to jump to an excited state (outer level)

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A 55-kg woman is wearing high heels.

Grace [21]

Answer:

Pressure, $P=1.90\times 10^7\ Pa$

Explanation:

It is given that,

Mass of the woman, m = 55 kg

Diameter of the circular cross section, d = 6 mm

Radius, r = 3 mm = 0.003 m

Let P is the pressure exerted on the floor. It is equal to the force acting on woman per unit area. It is given by :

$P=\dfrac{F}{A}$

$P=\dfrac{mg}{\pi r^2}$

$P=\dfrac{55\times 9.8}{\pi (0.003)^2}$

$P=1.90\times 10^7\ Pa$

So, the pressure exerted on the floor is $1.90\times 10^7\ Pa$ . Hence, this is the required solution.

7 0

3 years ago

A 35.4 kg girl is riding on the back of a 15.23 kg cart. the cart and the kid are both moving eastward at 4.25 m/s when she step

Grace [21]

Answer:

The final velocity of the cart is $v_c = 7.02 \ m/s$

Explanation:

From the question we are told that

The mass of the girl is $m_g = 35.4 \ kg$

The mass of the cart is $m_c = 15.23 \ kg$

The speed of the cart and kid(girl) is $v = 4.25 \ m/s$

The final velocity of the girl is $v_g = 3.06 \ m/s$

Let assume that velocity eastward is positive and velocity westward is negative (Note that if we assume vise versa it wouldn't affect the answer )

The total momentum of the system before she steps off the back of the cart

is mathematically evaluated as

$p__{T1}} = (m_g + m_c) * v$

substituting values

$p__{T1}} = (35.4 + 15.23) * 4.25$

$p__{T1}} =215.17 \ kg m /s$

The total momentum after she steps off the back of the cart is mathematically evaluated as

$p__{T2}} = (m_g * v_g ) +( m_c * v_c )$

Where $v_c$ is the final velocity of the cart

substituting values

$p__{T2}} = (35.4 * 3.06 ) +( 15.23 * v_c )$

$p__{T2}} = 108. 324 + 15.23 v_c$

Now according to the law of conservation of momentum

$p__{T1}} =p__{T2}}$

$215.17 \ kg m /s = 108. 324 + 15.23 v_c$

=> $v_c = 7.02 \ m/s$

Since the value is positive it implies that the cart moved eastward

7 0

3 years ago

Help me besties ok thx

Pachacha [2.7K]

Answer:

$1 \\ 0.5 \times 500 \times 20 \times 20 \\ \ 2 \\ 0.5 \times 0.6 \times 100 \times 100 \\ 3 \\ 1000 \times 0.5 \times 10 \times 10 \\ 1000 \times 0.5 \times 20 \times 20 \\ 1000 \times 0.5 \times 30 \times 30 \\ 4 \\ 0.5 \times 40000 \times 30 \times 30 \\ 5 \\ \sqrt{ \frac{2}{0.1 \times 0.5} }$

7 0

2 years ago

the current flowing in an appliance connected to a 120V source is 2A. How many kilowatt-hours of electrical energy does the appl

skad [1K]

Answer:

0.96 kWh

Explanation:

First of all, we can find the power of the appliance using the formula:

$P=VI$

where

V = 120 V is the voltage of the source

I = 2 A is the current

Substituting,

$P(120 V)(2 A)=240 W = 0.24 kW$

Now we want to find the amount of energy used by the applied in a time of

t = 4 h

The amount of energy is given by

$E=Pt$

where

P = 0.24 kW

t = 4 g

Substituting,

$E=(0.24 kW)(4 h)=0.96 kWh$

8 0

3 years ago

I NEED HELP!!!!! PLEASE ANSWER! FIRST CORRECT ANSWER WILL GET BRAINLIEST AND I WILL FOLLOW YOU!

Naily [24]

Average speed = (total distance) / (time to cover the distance)

We know:

Average speed = 65 km/hr
Total distance = 1,000 km
Time to cover it = (Driving Time) + 4 hours.

so we can write:

65 km/hr = (1,000 km) / (Driving Time + 4hr)

(I'm going to start calling the driving time 'DT'.
Notice that DT is a number with the units of 'hours'.)

Multiply each side by (DT + 4hr)

(65 km/hr) (DT + 4hr) = 1,000 km

Eliminate parentheses on the left side:

(65·DT km + 260 km) = 1,000 km

Subtract 260km from each side:

65·DT km = 740 km

Divide each side by 65 :

DT = 11.38 hours .

DT (Driving Time) is the time you spent actually driving.
You had to cover the complete 1,000 km in that time.
So while you were driving, you had to do it at a speed of

1,000 km / 11.38 hrs = 87.8 km/hr .
__________________________________________

As long as we're already totally bored by this question,
let's work on it some more, and check my answer:

... Driving for 11.38 hours at a speed of 87.8 km/hr, you cover

(11.38 hr) x (87.8 km/hr) = 999.164 km (close enough to 1,000) .

So far, so good. The distance is taken care of.

With the 4-hour stop, the total trip takes 4 more hours = 15.38 hours.
So the average speed is

(1,000 km) / (15.38 hr) = 65.02 km/hr

Close enough to 65 km/hr. yay !

6 0

3 years ago