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4 years ago

Explain why a reference points that are stationary are usually chosen to determine whether an object is in motion.

1 answer:

4 0

Answer: Stationary reference points are used to determine if a object is in motion because if the reference point is still,you will be able to see if the object is in motion. If you had a reference point that wasn't stationary, you wouldn't be able to tell if the object was in motion.

Explanation:

Stationary reference points are used to determine if a object is in motion because if the reference point is still,you will be able to see if the object is in motion. If you had a reference point that wasn't stationary, you wouldn't be able to tell if the object was in motion.

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A wave with a wavelength of 15m travel at 330m/s.Calculate its frequency.

katovenus [111]

ANSWER:

22 Hz.

Explanation:

Frequency = (speed) divided by (wavelength) = (330) / (15) =

8 0

3 years ago

) Water flows through a horizontal coil heated from the outside by high-temperature flue gases. As it passes through the coil th

Mademuasel [1]

Explanation:

Formula for steady flow energy equation for the flow of fluid is as follows.

$m[h_{1} + \frac{V^{2}_{1}}{2}] + z_{1}g] + q = m[h_{1} + \frac{V^{2}_{1}}{2} + z_{1}g] + w$

Now, we will substitute 0 for both $z_{1}$ and $z_{2}$ , 0 for w, 334.9 kJ/kg for $h_{1}$ , 2726.5 kJ/kg for $h_{2}$ , 5 m/s for $V_{1}$ and 220 m/s for $V_{2}$ .

Putting the given values into the above formula as follows.

$m[h_{1} + \frac{V^{2}_{1}}{2}] + z_{1}g] + q = m[h_{1} + \frac{V^{2}_{1}}{2} + z_{1}g] + w$

$1 \times [334.9 \times 10^{3} J/kg + \frac{(5 m/s)^{2}}{2} + 0] + q = 1 \times [2726.5 \times 10^{3} + \frac{(220 m/s)^{2}}{2} + 0] + 0$

q = 6597.711 kJ

Thus, we can conclude that heat transferred through the coil per unit mass of water is 6597.711 kJ.

6 0

4 years ago

At a objects highest point is the acceleration zero too?

puteri [66]

Answer:

Acceleration from gravity is always constant and downward, but the direction and magnitude of velocity change. At the highest point in its trajectory, the ball has zero velocity, and the magnitude of velocity increases again as the ball falls back toward the earth

Explanation:

5 0

4 years ago

Read 2 more answers

An office worker has his lunch on the 53rd floor of an office building. In which case is the gravitational potential energy of t

alekssr [168]

Answer: In all cases, gravitational potential energy, respect from a common reference level (street level for instance) is the same.

Explanation:

Gravitational potential energy, comes from the action of the gravitational field, which is a conservative one.

This means, that if someone does work against the field (for instance lifting a weight from the ground to a given height), and then drops the weight, the work done by the field will be exactly the same.

Otherwise, the object would have remaining energy after returning to the starting point, which would violate the laws of physics, specially Thermodynamic's 2nd Law.

For this reason, the gravitational potential energy only depends from the height, and is independent from the path taken to reach there.

0 0

4 years ago

When antimatter interacts with an equal mass of ordinary matter, both matter and antimatter are converted completely into energy

Ilya [14]

Answer:

v = 5.88 10⁷ m / s

Explanation:

For this exercise we use the relation

E = m c²

also indicate that all energy is converted into kinetic energy

E = K = ½ (M-2m) v²

where m is the mass of antimatter and M is the mass of the ship's mass. Factor two is due to the fact that equal amounts of matter and antimatter must be combined

we substitute

m c² = ½ (M-2m) v²

v² = $2 \frac{m}{M+2m} \ c^2$

let's calculate

v = $\sqrt{2 \ \frac{4 \ 10^4 }{2 \ 10^6 + 2 \ 4 \ 10^4} \ (3 \ 10^8)^2}$

v = $\sqrt{ 34.615 \ 10^{14}}$

v = 5.88 10⁷ m / s

8 0

3 years ago