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Gennadij [26K]
3 years ago
14

If a subway train is moving to the left (has a negative velocity) and then comes to a stop, what is the direction of its acceler

ation? Is the acceleration positive or negative?
Physics
1 answer:
Katen [24]3 years ago
8 0

Answer:

The acceleration would be positive, pointing to the right.

Explanation:

The acceleration tells us how velocity changes every second. If the train stops, this means its velocity must go from a non-zero value to zero.

To reduce velocity, acceleration must point to the opposite direction. Since velocity is negative, acceleration must be positive.

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What type of Literary Devices is this passage and provide an explanation
bekas [8.4K]

By the admiring tone that the writer has for the gift that she/he received, it is clear that there's a lot of imagery. The writer also described the rose as "perfect", "scented dew still wet", and "pure", which further supports the idea that he/she is describing the gift.

6 0
3 years ago
Read 2 more answers
A missile is moving 1350 m/s at a 25.0° angle. It needs to hit a target 23,500 m away in a 55.0° direction in 10.20 s. What is d
QveST [7]

Answer:

  The target's velocity is about 1320 m/s in the direction 265.7°.

Explanation:

In order for there to be a collision between missile and target, we must have ...

  (target starting position) + (target movement) = (missile movement)

assuming the missile starts from the origin of all measurements. The missile moves 10.2 seconds before impact, so moves a distance of ...

  (10.2 s)(1350 m/s) = 13,770 m

__

We are interested in the target movement, so we can solve for that:

  (target movement) = (missile movement) - (target starting position)

In terms of meters, this is ...

  (target movement) = 13770∠25° - 23500∠55° ≈ 13467.74∠-94.3°

The target covers this distance in the same 10.2 seconds before collision, so its speed is (13467.74 m)/(10.2 s) ≈ 1320.4 m/s.

As a positive angle, the target's direction is ...

  -94.3° +360° = 265.7°

The direction of the target's velocity is 265.7°.

_____

If you're calculating this by hand, there are a couple of ways you can do it. You can convert to rectangular coordinates and back (perhaps least confusing), or you can use the law of cosines to solve the triangle, then translate angles back to the x-y coordinate plane.

Using rectangular coordinates, we have ...

  13770∠25° = 13770(cos(25°), sin(25°)) ≈ (12479.9, 5819.45)

  23500∠55° = 23500(cos(55°), sin(55°)) ≈ (13479.0, 19250.1)

Then the difference is ...

  (12479.9, 5819.45) -(13479.0, 19250.1) ≈ (-999.188, -13430.6)

and the (3rd-quadrant) angle is ...

  target direction = arctan(-13430.6/-999.188) ≈ -94.3° = 265.7°

__

The target's speed is found by dividing the distance it covers by the time it takes.

  √(13430.6² +999.188²)/10.2 ≈ 1320.36 . . . m/s

3 0
3 years ago
Explain what differentiates the Earth’s crust and lithosphere.
Allisa [31]

Answer:

What is the difference between the crust and lithosphere? The crust (whether continental or oceanic) is the thin layer of distinctive chemical composition overlying the ultramafic upper mantle. ... The lithosphere is the rigid outer layer of the Earth required by plate tectonic theory.

Explanation:

Hope this helps!

4 0
2 years ago
Read 2 more answers
Observe: Air pressure is equal to the weight of a column of air on a particular location. Airpressure is measured in millibars (
lesya [120]

Answer:

a) When moving towards a high pressure center the pressure values ​​increase in the equipment

b) This area is called high prison since the weight of the atmosphere on top is maximum

Explanation:

A) A high atmospheric pressure system is an area where the pressure is increasing the maximum value is close to 107 Kpa, the other side as low pressure can have small values ​​85.5 kPa.

When moving towards a high pressure center the pressure values ​​increase in the equipment

B) This area is called high prison since the weight of the atmosphere on top is maximum

in general they are areas of good weather

6 0
3 years ago
If a lamp has a resistance of 50 ohms and is operated by a p.d. of 10V, find the current flowing through it
NemiM [27]
V=IR therefore I=V/R=10/50=0.2A therefore the current is 0.2 A
4 0
2 years ago
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