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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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An ___ is a deep valley on land that forms along a divergent boundary
Gennadij [26K]
This is a Rift Valley. 

Hope this helped!
7 0
2 years ago
Read 2 more answers
Two satellites A and B orbit the Earth in the same plane. Their masses are 5 m and 7 m, respectively, and their radii 4 r and 7
Dmitry [639]

Answer:

The ratio of their orbital speeds are 5:4.

Explanation:

Given that,

Mass of A = 5 m

Mass of B = 7 m

Radius of A = 4 r

Radius of B = 7 r

The orbital speed of satellite A,

v_{A}=\sqrt{\dfrac{GM_{A}}{R_{A}}}......(I)

The orbital speed of satellite B,

v_{B}=\sqrt{\dfrac{GM_{B}}{R_{B}}}......(I)

We need to calculate the ratio of their orbital speeds

Using equation (I) and (II)

\dfrac{v_{A}}{v_{B}}=\sqrt{\dfrac{\dfrac{GM_{A}}{R_{A}}}{\dfrac{GM_{B}}{R_{B}}}}

Put the value into the formula

\dfrac{v_{A}}{v_{B}}=\sqrt{\dfrac{G\times5m\times7r}{G\times7m\times4r}}

\dfrac{v_{A}}{v_{B}}=\dfrac{5}{4}

Hence, The ratio of their orbital speeds are 5:4.

8 0
3 years ago
An airplane accelerates from a velocity of 22 m/s to 40 m/s with an acceleration of 2 m/s2. How long does it
andrey2020 [161]

The time it takes the plane to change its velocity is 9s.

<h3>What is time?</h3>

Time can be defined the measured or measurable period during which an action, process, or condition exists or continues.

To calculate the time it takes the airplane to change its velocity, we use the formula below.

Formula:

  • t = (v-u)/a.......... Equation 1

Where:

  • a = Acceleration
  • v = Final velocity
  • u = Initial velocity
  • t = time

From the question,

  • v = 40 m/s
  • u = 22 m/s
  • a = 2 m/s²

Substitute these values into equation  1

  • t = (40-22)/2
  • t = 18/2
  • t = 9s

Hence, the time it takes the plane to change its velocity is 9s.

Learn more about time here: brainly.com/question/2854969

4 0
1 year ago
Which law represents the thermodynamic statement of the conservation of energy of a system
Tresset [83]
The law of conservation of energy is a law of science that states that energy cannot be created or destroyed, but only changed from one form into another or transferred from one object to another.<span>

</span>
3 0
3 years ago
If the v – t graph of a particle is parallel to the t – axis the body has (a) uniform velocity (b) uniform acceleration (c) zero
maxonik [38]

Answer:

zero  velocity

Explanation:

if the v-t graph is parallel to the time axis its mean body has covered no path in other words the body is at rest so the velocity of the body should be zero

hope my answer will helps u plz mark me brainlist

5 0
2 years ago
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