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julia-pushkina [17]
3 years ago
8

A construction worker ascending at 6m/s in an open elevator 42 m above the ground drops a hammer.

Physics
1 answer:
earnstyle [38]3 years ago
6 0
Let us follow the motion of the hammer first. Because the elevator is in motion, when he drops the hammer, because of inertia, there is a slight moment when the hammer also rises with the elevator. Eventually it will reach its highest peak and drop down to the floor. So, the total time for the hammer to reach the floor would include: (1) the time for it to rise with the elevator to its highest peak and (2) the time for the free fall from the highest peak to the floor.

1.) Time for it to rise with the elevator to its highest peak:
      Hmax = v²/2g = (6 m/s)²/2(9.81 m/s²) = 1.835 m
      Time to reach 1.835 m = 1.835 m * 1 s/6 m = 0.306 s
     
     Time for the free fall from the highest peak to the floor:
      t = √2y/g, where y is the total height
      y = 1.835 m + 42 m = 43.835 m
      So,
      t = √2(43.835 m )/(9.81 m/s²) = 2.989 s

      Therefore, the total time is 0.306 s + 2.989 s = 3.3 seconds

2.) Velocity of impact of a free-falling body is:
      v = √2gy
      v = √2(9.81 m/s²)(43.835 m)
      v = 29.33 m/s
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3 years ago
An object is given a very small amount of charge. Which of the following could
spayn [35]

5.4*10^-19 C

Explanation:

For the purposes of this question, charges essentially come in packages that are the size of an electron (or proton since they have the same magnitude of charge). The charge on an electron is -1.6*10^-19

Therefore, any object should have a charge that is a multiple of the charge of an electron - It would not make sense to have a charge equivalent to 1.5 electrons since you can't exactly split the electron in half. So the charge of any integer number of electrons can be transferred to another object.

Charge = q(electron)*n(#electrons)

Since 5.4/1.6 = 3.375, we know that it can not be the right answer because the answer is not an integer.

If you divide every other option listed by the charge of an electron, you will get an integer number.

(16*10^-19 C)/(1.6*10^-19C) = 10

(-6.4*10^-19 C)/(1.6*10^-19C) = -4

(4.8*10^-19 C)/(1.6*10^-19C) = 3

(5.4*10^-19 C)/(1.6*10^-19C) = 3.375

(3.2*10^-19C)/(1.6*10^-19C) = 2

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I hope this helps!

3 0
3 years ago
What is the the steadiest firing position?
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A force of 45 newtons is applied on an object, moving it 12 meters away in the same direction as the force. What is the magnitud
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If the applied force is in the same direction as the object's displacement, the work done on the object is:

W = Fd

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5 0
3 years ago
A gun shoots a bullet with a velocity of 500 m/s. The gun is aimed horizontally and fired from a height of 1.5 m. How far does t
MrMuchimi

The bullet travels a horizontal distance of 276.5 m

The bullet is shot forward with a horizontal velocity u_x. It takes a time <em>t</em> to fall a vertical distance <em>y</em> and at the same time travels a horizontal distance <em>x. </em>

The bullet's horizontal velocity remains constant since no force acts on the bullet in the horizontal direction.

The initial velocity of the bullet has no component in the vertical direction. As it falls through the vertical distance, it is accelerated due to the force of gravity.

Calculate the time taken for the bullet to fall through a vertical distance <em>y </em>using the equation,

y=u_yt+\frac{1}{2} gt^2

Substitute 0 m/s for u_y, 9.81 m/s²for <em>g</em> and 1.5 m for <em>y</em>.

y=u_yt+\frac{1}{2} gt^2\\ 1.5 m=(0m/s)t+\frac{1}{2} (9.81m/s^2)t^2\\ t=\sqrt{\frac{2(1.5m)}{9.81m/s^2} } =0.5530s

The horizontal distance traveled by the bullet is given by,

x=u_xt

Substitute 500 m/s for u_x and 0.5530s for t.

x=u_xt\\ =(500m/s)(0.5530s)\\ =276.5m

The bullet travels a distance of 276.5 m.


5 0
3 years ago
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