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Igoryamba
3 years ago
7

Phase change requires...

Physics
1 answer:
amm18123 years ago
3 0
<span>Evaporation involves a liquid becoming a gas and sublimation is the change of a solid directly to a gas.Phase changes require either the addition of heat energy (melting, evaporation, and sublimation) or subtraction of heat energy (condensation and freezing.</span>
You might be interested in
Which is the most abundant element in the Sun?
Delvig [45]
The answer is hydrogen.
5 0
3 years ago
A train is accelerating at a rate of 2 km/hr/s.  If its initial velocity is 20 km/hr, what is its velocity after 30 seconds?
Mademuasel [1]
Here it is. *WARNING* VERY LONG ANSWER

________________________________________... 
<span>11) If Galileo had dropped a 5.0 kg cannon ball to the ground from a height of 12 m, the change in PE of the cannon ball would have been product of mass(m),acceleration(g)and height(h) </span>

<span>The change in PE =mgh=5*9.8*12=588 J </span>
<span>______________________________________... </span>
<span>12.) The 2000 Belmont Stakes winner, Commendable, ran the horse race at an average speed = v = 15.98 m/s. </span>

<span>Commendable and jockey Pat Day had a combined mass =M= 550.0 kg, </span>

<span>Their KE as they crossed the line=(1/2)Mv^2 </span>

<span>Their KE as they crossed the line=0.5*550*(15.98)^2 </span>

<span>Their KE as they crossed the line is 70224.11 J </span>

<span>______________________________________... </span>
<span>13)Brittany is changing the tire of her car on a steep hill of height =H= 20.0 m </span>

<span>She trips and drops the spare tire of mass = m = 10.0 kg, </span>

<span>The tire rolls down the hill with an intial speed = u = 2.00 m/s. </span>

<span>The height of top of the next hill = h = 5.00 m </span>

<span>Initial total mechanical energy =PE+KE=mgH+(1/2)mu^2 </span>

<span>Initial total mechanical energy =mgH+(1/2)mu^2 </span>

<span>Suppose the final speed at the top of second hill is v </span>

<span>Final total mechanical energy =PE+KE=mgh+(1/2)mv^2 </span>

<span>As mechanical energy is conserved, </span>

<span>Final total mechanical energy =Initial total mechanical energy </span>

<span>mgh+(1/2)mv^2=mgH+(1/2)mu^2 </span>

<span>v = sq rt [u^2+2g(H-h)] </span>

<span>v = sq rt [4+2*9.8(20-5)] </span>

<span>v = sq rt 298 </span>

<span>v =17.2627 m/s </span>

<span>The speed of the tire at the top of the next hill is 17.2627 m/s </span>
<span>______________________________________... </span>
<span>14.) A Mexican jumping bean jumps with the aid of a small worm that lives inside the bean. </span>

<span>a.)The mass of bean = m = 2.0 g </span>

<span>Height up to which the been jumps = h = 1.0 cm from hand </span>

<span>Potential energy gained in reaching its highest point= mgh=1.96*10^-4 J or 1960 erg </span>

<span>b.) The speed as the bean lands back in the palm of your hand =v=sq rt2gh =sqrt 0.196 =0.4427 m/s or 44.27 cm/s </span>
<span>_____________________________ </span>
<span>15.) A 500.-kg horse is standing at the top of a muddy hill on a rainy day. The hill is 100.0 m long with a vertical drop of 30.0 m. The pig slips and begins to slide down the hill. </span>

<span>The pig's speed a the bottom of the hill = sq rt 2gh = sq rt 2*9.8*30 =sq rt 588 =24.249 m/s </span>
<span>__________________________________ </span>
<span>16.) While on the moon, the Apollo astronauts Neil Armstrong jumped up with an intitial speed 'u'of 1.51 m/s to a height 'h' of 0.700 m, </span>

<span>The gravitational acceleration he experienced = u^2/2h = 2.2801 /(2*0.7) = 1.629 m/s^2 </span>
<span>______________________________________... </span>

<span>EDIT </span>
<span>1.) A train is accelerating at a rate = a = 2.0 km/hr/s. </span>

<span>Acceleration </span>

<span>Initial velocity = u = 20 km/hr, </span>

<span>Velocity after 30 seconds = v = u + at </span>

<span>Velocity after 30 seconds = v = 20 km/hr + 2 (km/hr/s)*30s = </span>

<span>Velocity after 30 seconds = v = 20 km/hr + 60 km/hr = 80 km/ hr </span>

<span>Velocity after 30 seconds = v = 80 km/hr=22.22 m/s </span>
<span>_______________________________- </span>
<span>2.) A runner achieves a velocity of 11.1 m/s 9 s after he begins. </span>

<span>His acceleration = a =11.1/9=1.233 m/s^2 </span>

<span>Distance he covered = s = (1/2)at^2=49.95 m</span>
7 0
3 years ago
If your heart is beating at 76. 0 beats per minute, what is the frequency of your heart's oscillations in hertz?
nikitadnepr [17]

If the heart is beating at 76. 0 beats per minute, the Frequency of heart's oscillations in hertz is 1.25 Hertz.

The Frequency is defined as the number of oscillations completed in 1s.

Our heart beats continuously giving rise to the frequency of the heart.

Measuring frequency would be possible if we measure the time in seconds.

75 beats per minute means that 75 beats occur in 60s.

Frequency = Number of beats / Total time taken

Frequency = 75 / 60

Frequency = 1.25 Hz

Hence, number of beats per second is 1.25 Beats.

Beats per second or Cycles per second is same as the frequency of oscillation called as Hertz (Hz)

Hence, frequency of the heart oscillation is 1.25 Hertz (Hz).

Learn more about Frequency here, brainly.com/question/14316711

#SPJ4

5 0
2 years ago
6.A string of 100 Christmas lights requires 4 Volts and 2 Amps for a single bulb to light up. (a) When one light on the sting go
Molodets [167]

Answer:

Explanation:

From the information given,

V = 4 volts

A = 2 amps

a)

In the first instance, one light on the sting goes out and the whole string of lights no longer turns on. This means that the circuit is a series circuit.

b) Total voltage = 4 x 100 = 400 V

The current passing through each bulb is the same. Thus

Total Current = 2 Amps

Recall, V = IR

R = V/I

Thus,

Resistance = 400/2

Resistance = 200 ohms

c) In this case, one light goes out on the string all other lights still turn on. This means that the circuit is a parallel circuit

d)

The voltage is the same

Total voltage = 4 volts

Total current = 2 x 100 = 200 amps

Total resistance = 4/200

Total resistance = 0.02 ohms

3 0
1 year ago
Electrical resistance is measured in
devlian [24]
Resistance is the ratio of
 
         (voltage between two points in the circuit)
divided by
         (current between the same points).

It's expressed in units of Ohms, so the correct choice is "none of the above".
8 0
4 years ago
Read 2 more answers
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