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rosijanka [135]
3 years ago
15

Physics pls help

Physics
2 answers:
seropon [69]3 years ago
3 0
First one is correct
WARRIOR [948]3 years ago
3 0

Answer: -0.33m/s (A)

Explanation:

According to the law of conservation of momentum, the sum of momentum before collision is equal to sum of their momentum after collision. They move with the same velocity (v) after collision.

Momentum = mass × velocity

For 4kg mass with velocity of 3m/s,

Its momentum = 4×3 = 12kgm/s

For 8kg mass with velocity of 2m/s,

Its momentum = 8 × -2 = -16kgm/s.

The velocity of 8kg mass is negative because it is moving towards the left(-ve x-direction).

Sum of momentum before collision = 12+(-16) = -4kgm/s... (1)

Momentum of 4kg body after collision = 4v

Momentum of 8kg body after collision = 8v

Sum of momentum after collision = 4v+8v = 12v...(2)

Equating 1 and 2 according to law of conservation of momentum, we have;

-4 = 12v

V = -4/12

V = -0.33m/s

Therefore their velocity after collision is -0.33m/s

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A boy jumps from rest, straight down from the top of a cliff. He falls halfway down to the water below in 0.866 s. How much time
Iteru [2.4K]
<h2>Entire trip takes 1.22 seconds.</h2>

Explanation:

We have equation of motion s = ut + 0.5 at²

        Initial velocity, u = 0 m/s

        Acceleration, a = 9.81 m/s²  

        Time, t = 0.866 s      

     Substituting

                      s = ut + 0.5 at²

                      s = 0 x 0.866 + 0.5 x 9.81 x 0.866²

                      s = 3.68 m

      Halfway is 3.68 m

Total height = 2 x 3.68 = 7.36 m

We have equation of motion s = ut + 0.5 at²

        Initial velocity, u = 0 m/s

        Acceleration, a = 9.81 m/s²  

        Time, t = ?

        Displacement, s  = 7.36 m

     Substituting

                      s = ut + 0.5 at²

                      7.36 = 0 x t + 0.5 x 9.81 x t²

                      t = 1.22 s

Entire trip takes 1.22 seconds.

7 0
3 years ago
If the bar magnet is flipped over and the south pole is brought near the hanging ball, the ball will be?
disa [49]

The ball may attracted to the magnet.

<h3>How can we understand that the hanging ball will be attracted to the magnet or not?</h3>
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  • As we know, in this type of experiments of bar magnet most of the times the ball is made out of steel.
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  • This can be compared to how neutral objects also gets attracted to the positively and negatively charged rods through the Polarization force.

So, If the bar magnet is flipped over and the south pole is brought near the hanging ball, The ball will be attracted to the magnet.

Learn more about the bar magnet:

brainly.com/question/27943723

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7 0
1 year ago
Why do astronauts' weights differ in space?
OLga [1]

Answer:

There is less gravitational force in space.

Explanation:

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During a workout, the football players at State U ran up the stadium stairs in 61 s. The stairs are 130 m long and inclined at a
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Answer:

  P = 1097 Watt

Explanation:

given,

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inclination with horizontal,θ = 30°

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time = 61 s

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now,

P = \dfrac{66885}{61}

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hence, the power output on the way is 1097 W

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2 years ago
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