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Talja [164]
1 year ago
7

If the resultant force acting on a 2.0 kg object is equal to (3.0î + 4.0ĵ) N, what is the change in kinetic energy as the object

moves from (7.0î – 8.0ĵ) m to (11.0î – 5.0ĵ) m?
Physics
1 answer:
12345 [234]1 year ago
3 0

Answer:

ΔK = 24 joules.

Explanation:

ΔK = Work done on the object

Work is equal to the dot product of force supplied and the displacement of the object.

W = F * Δs

Δs can be found by subtracting the vectors (7.0, -8.0) and (11.0, -5.0), which is written as Δs = (11.0 - 7.0, -5.0 - -8.0) which equals (4.0, 3.0).

This gives us

W = < 3, 4 > * < 4, 3 > = (3*4)+(4*3) = 24 J

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Water is boiled at sea level in a coffeemaker equipped with an immersion-type electric heating element. The coffee maker contain
Luden [163]

Answer:

P=1362\ W

t'=251.659\ s is time required to heat to boiling point form initial temperature.

Explanation:

Given:

initial temperature of water, T_i=18^{\circ}C

time taken to vapourize half a liter of water, t=18\ min=1080\ s

desity of water, \rho=1\ kg.L^{-1}

So, the givne mass of water, m=1\ kg

enthalpy of vaporization of water, h_{fg}=2256.4\times 10^{-3}\ J.kg^{-1}

specific heat of water, c=4180\ J.kg^{-1}.K^{-1}

Amount of heat required to raise the temperature of given water mass to 100°C:

Q_s=m.c.\Delta T

Q_s=1\times 4180\times (100-18)

Q_s=342760\ J

Now the amount of heat required to vaporize 0.5 kg of water:

Q_v=m'\times h_{fg}

where:

m'=0.5\ kg= mass of water vaporized due to boiling

Q_v=0.5\times 2256.4

Q_v=1.1282\times 10^{6}\ J

Now the power rating of the boiler:

P=\frac{Q_s+Q_v}{t}

P=\frac{342760+1128200}{1080}

P=1362\ W

Now the time required to heat to boiling point form initial temperature:

t'=\frac{Q_s}{P}

t'=\frac{342760}{1362}

t'=251.659\ s

6 0
3 years ago
Which are properties of a liquid? Check all that apply.
Strike441 [17]

Answer:

the property of liquid are

1 they can flow from one place to another if surface is slanted

2 it cannot be compressed

6 0
3 years ago
Suppose the current in a conductor decreases exponentially with time according to the equation I(t) = I0e-t/τ, where I0 is the i
ELEN [110]

Answer:

Pls see attached file

Explanation:

5 0
3 years ago
Fifteen grams of substance X at 95 degrees Celsius is mixed with 45 grams of substance Z at 85 degrees Celsius in a container wh
Viefleur [7K]
According to the Law of Conservation of Energy, energy is neither created nor destroyed. They are just transferred from one system to another. To obey this law, the energy of the substances inside the container must be equal to the substance added to it. The energy is in the form of heat. There can be two types of heat energy: latent heat and sensible heat. Sensible heat is energy added or removed when a substance changes in temperature. Latent heat is the energy added or removed at a constant temperature during a phase change. Since there is no mention of phase change, we assume the heat involved here is sensible heat. The equation for sensible heat is:

H = mCpΔT
where
m is the mass of the substance
Cp is the specific heat of a certain type of material or substance
ΔT is the change in temperature.

So the law of conservation of heat tells that:

Sensible heat of Z + Sensible heat of container = Sensible heat of X

Since we have no idea what these substances are, there is no way of knowing the Cp. We can't proceed with the calculations. So, we can only assume that in the duration of 15 minutes, the whole system achieves equilibrium. Therefore, the equilibrium temperature of the system is equal to 32°C. The answer is C.
5 0
3 years ago
when a person uses an iron to remove the wrinkles from a shirt, why does heat travel from the iron to the shirt?
artcher [175]
I think the answer to your question is that:
There is chemical energy being produced (by the water) and that causes the base of iron to absorb the heat. Then when the heated base of the iron is placed onto the shirt, the heat flattens the wrinkles on it.
3 0
3 years ago
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