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2 years ago

The energy transferred to the water in 100 seconds was 155 000 J. specific heat capacity of water = 4200 J/kg °C

Physics

2 answers:

Otrada [13]2 years ago

5 0

Answer:

0.47kg

Explanation:

1. find the change in temperature (the start point of the straight line)

100-22= 78 degrees celsius

2. use specific heat capacity equation

change in thermal energy (J) = m x J/kg C X 78

155000= m x 4200 x 78

3. rearrange to find m

155000/(4200x78)

4200x78= 327600

155000/327600= 0.4731379

2sf= 0.47kg

skelet666 [1.2K]2 years ago

4 0

Answer:

0.37 kg

Explanation:

I'm not a professor myself, but this is how I worked it out:

using the graph, after 100 seconds, the temperature is 100 degrees Celsius.

If we now substitute everything into the specific heat capacity equation, making the mass "m", we would come up with:

4200 = 155000/(m x 100)

If we rearrange and solve for m, we get 0.37 kg.

I'm not sure if I have done this correctly, feel free to correct me.

Hope this helps!

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ludmilkaskok [199]

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I'll leave out units for neatness: I(t) = 0.6e^(-t/6)

If t is in seconds then since 1hr = 3600s: I(t) = 0.6e^(-t/(6 x 3600) ).

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Q = ∫(0.6e^(-kt)

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= 0.6/k

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2 years ago

If an electromagnetic wave has components Ey = E0 sin(kx - ωt) and Bz = B0 sin(kx - ωt), in what direction is it traveling?

fomenos

Answer:

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Explanation:

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4m at 1.2 radian means 4m at $68.75^0$

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6m at $-210^0$ can be written as 6*cos $(-210)^0$ i+6*sin $(-210)^0$ j = -5.20i-3j

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2 years ago

A 36,287 kg truck has a momentum of 907,175 kg • m/s. What is the trucks velocity.

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2 years ago

A body is projected upward at an angle of 30 degree to the horizontal at an initial speed of 200ms-.In how many seconds will it

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Answer:

20.41 s

3534.80 m

Explanation:

In how many seconds will it reach the ground?

We are given the initial velocity of the body, which is 200 m/s at a 30° angle.

We know the acceleration in the vertical direction is -9.8 m/s², assuming that the upwards/right direction is positive and the downwards/left direction is negative.

Since we are using acceleration in the y-direction, let's use the vertical component of the initial velocity.

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Let's use the fact that at the top of its trajectory, the body will have a final velocity of 0 m/s.

Now we have one missing variable that we are trying to solve for: time t.

Find the constant acceleration equation that contains v₀, v, a, and t.

v = v₀ + at

Substitute known values into the equation.

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The body will reach the ground in 20.41 seconds.

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We want to find the displacement in the x-direction for the body.

Let's find the constant acceleration equation that contains time t, that we just found, and displacement (Δx).

Δx = v₀t + 1/2at²

Substitute known values into the equation. Remember that we want to use the horizontal component of the initial velocity and that the acceleration in the x-direction is 0 m/s².

Δx = (200 · cos(30) · 20.40816327) + 1/2(0)(20.40816327)²
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The body will strike 3534.80 m from the point of projection.

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1 year ago