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4 years ago

8

crystal of a chemical in a lab slowly disappear from their container they do not become liquid this is an example of which chang

e of state

1 answer:

Akimi4 [234]4 years ago

6 0

The answer is D sublimation

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The coach has not seen improvement as expected in his team and plans to change practice session. To help the players he changes

Allushta [10]

Answer:

progession

Explanation:

7 0

3 years ago

A sailboat weighing 980 lb with its occupants is running downwind at 8 mi/h when its spinnaker is raised to increase its speed.

Effectus [21]

Answer:

78.498N

Explanation:

The Net force provided by the spinnaker can be obtained from Newton's second law of motion as follows;

$F=\frac{m(v-u)}{t}................(1)$

where m is the mass, v is the final velocity, u is the initial velocity and t is the time interval for which the force acted.

Given;

m =980lb

v = 12mi/h

u =8mi/hr

t = 10s.

It is important to convert all quantities to their SI units where necessary, so we do that as follows;

1lb = 0.45kg,

hence 980lb = 980 x 0.45kg = 441kg.

1mile = 1609.34m

1hour = 3600s,

therefore;

$8mi/h=\frac{8*1609.34m}{3600s}=3.58m/s$

$12mi/h=\frac{12*1609.34m}{3600s}=5.36m/s$

Substituting all values into equation (1), we obtain the following;

$F=\frac{441(5.36-3.58)}{10}\\F=\frac{441*1.78}{10}\\F=\frac{784.98}{10}\\F=78.498N$

4 0

3 years ago

PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!

mestny [16]

C standards are based on observable, reproducible natural phenomena.

3 0

3 years ago

Some of the following statements regarding heat exchangers is (are) wrong, namely (A) Heat exchangers are devices where two movi

DaniilM [7]

Answer:

A,B,D,E are wrong

(A) Heat exchangers are devices where two moving fluid streams are mixed together (B) Heat exchangers are devices where two moving fluid streams exchange mass (D) Heat exchangers are devices where two moving fluid streams exchange mechanical work without mixing together (E) There is no heat transfer between the two fluids of an insulated heat exchanger

Explanation:

A heat exchanger can be regarded as a system that bring about transfer heat between two or more than two fluids. It can function in cooling process and heating processes, the fluids involves in this process can have a solid wall to separate them so as to prevent mixing, direct contact could also be utilized. The mechanism is making hot gas jets which could fire upward over a glowing water that is passing through pipes, as water moves along the pipe, heat energy is been absorbed and there is heating up i.e heat is transferred. One is cooked the other is heated up. It is very essential to insulate the whole steam system along with heat exchangers so that energy could be saved and the temperature of the surface would be at safe-to-touch range and also steam quality could be maintained. The types of heat exchanger we have are;

✓Shell and tube heat exchangers.

✓Condensers, evaporators, and boilers

✓Double pipe heat exchangers.

✓Plate heat exchangers.

It should be noted Heat exchangers are devices where two moving fluid streams exchange heat (thermal energy) without mixing together

3 0

3 years ago

A 0.54 kg air hockey puck is initially at rest. What will it's kinetic energy energy be after a net force of 0.56 N acts on it f

Rufina [12.5K]

Answer:

Kf = 470 mJ

Explanation:

According the work-energy theorem, the change in the kinetic energy of one object, is equal to the net work done on it.
Since the puck is initially at rest, the change is kinetic energy is just the final kinetic energy of the puck.
Assuming that the net force is horizontal, and causes a horizontal displacement also, we can find the net work on the puck as follows:

$W_{net} = F_{net} * \Delta X = 0.56 N * 0.84 m = 0.47 J = 470 mJ (1)$

As we have already said, (1) is equal to the final kinetic energy of the puck:
⇒ Kf = 470 mJ (2)

8 0

3 years ago