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Mila [183]
4 years ago
10

A car accelerates uniformly in a straight line

Physics
1 answer:
julia-pushkina [17]4 years ago
8 0

The car travels a distance <em>d</em> from rest with acceleration <em>a</em> after time <em>t</em> of

<em>d</em> = 1/2 <em>a</em> <em>t</em>²

It covers 69 m with 2.8 m/s² acceleration, so that

69 m = 1/2 (2.8 m/s²) <em>t</em>²

<em>t</em>² = 2 (69 m) / (2.8 m/s²)

<em>t</em> ≈ 7.02 s

where we take the positive square root because we're talking about time *after* the car begins accelerating.

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I would think it would be the same if you are weighting the dish and the Ice cube at the same time anyway. Not to sure though I'm a beginner and math is complicated for me sometimes.
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4 years ago
A flat roof is very susceptible to wind damage during a thunderstorm and/or tornado. If a flat roof has an area of 500 m2 and wi
Evgesh-ka [11]

Answer: The magnitude of the force exerted on the roof is 490522.5 N.

Explanation:

The given data is as follows.

Below the roof, v_{1} = 0 m/s

At top of the roof, v_{2} = 39 m/s

We assume that P_{1} is the pressure at lower surface of the roof and P_{2} be the pressure at upper surface of the roof.

Now, according to Bernoulli's theorem,

P_{1} + 0.5 \times \rho \times v^{2}_{1} = P_{2} \times 0.5 \rho \times v^{2}_{2}

P_{1} - P_{2} = 0.5 \times \rho \times (v^{2}_{2} - v^{2}_{1})

             = 0.5 \times 1.29 \times [(39)^{2} - (0)^{2}]

             = 0.645 \times 1521

             = 981.045 Pa

Formula for net upward force of air exerted on the roof is as follows.

          F = (P_{1} - P_{2})A

             = 981.045 \times 500

             = 490522.5 N

Therefore, we can conclude that the magnitude of the force exerted on the roof is 490522.5 N.

5 0
3 years ago
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Answer:

Nothing is more important to us on Earth than the Sun. Without the Sun's heat and light, the Earth would be a lifeless ball of ice-coated rock. The Sun warms our seas, stirs our atmosphere, generates our weather patterns, and gives energy to the growing green plants that provide the food and oxygen for life on Earth.

Explanation:

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Montano1993 [528]

-- Gravity adds 9.8 m/s to the downward speed of any object, every second ... as long as there are no other forces messing with it.

-- In 0.6 sec, gravity added (0.6x9.8)= 5.88 m/s to the downward speed of this ball.

-- This ball didn't start from zero. You threw it down with an initial speed of 1 m/s. So after 0.6 sec, with the help of gravity, its speed is

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Pick choice-C .

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