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schepotkina [342]

1 year ago

5

The Earth has a magnetic field around it, which is generated by its molten core. This magnetic field exerts a force on compass d

ials, which are magnets, causing them to align with the Earth's magnetic field.
This force on compass dials is an example of a force that _______.

A.
acts only on contact.
B.
needs electricity to act.
C.
acts through particles in the air.
D.
acts at a distance.

2 answers:

lukranit [14]1 year ago

6 0

This force on compass dials is an example of a force that acts at a distance. (A compass doesn't need to touch the molten core of the Earth in order to work correctly.)

aleksley [76]1 year ago

4 0

acts at a distance thats the right one

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B.

The child is too old to be gaining something from the screen time.

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Suppose we replace the mass in the video with one that is four times heavier. How far from the free end must we place the pivot

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We must place the pivot to keep the meter stick in balance at 90 cm (10 cm from the weight) from the free end.

Answer: Option B

<u>Explanation:</u>

In initial stage, the meter stick’s mass and mass hanged in meter stick at one end are same. Refer figure 1, the mater stick’s weight acts at the stick’s mid-point.

If in case, the meter stick is to be at balanced form, then the acting torques sum would be zero. So,

$m \times g \times(x)+((m \times g)(x-50 \mathrm{cm}))=0$

$(m \times g \times x)-(50 \times m \times g)+(m \times g \times x)=0$

Taking out ‘mg’ as common and we get

$2 x-50=0$

$2 x=50$

$x=\frac{50}{2}=25 \mathrm{cm}$

Hence, the stick should be pivoted at a distance of,

$x^{\prime}=100 \mathrm{cm}-25 \mathrm{cm}=75 \mathrm{cm}$

So, the stick should be pivoted at a distance of 75 cm at the free end

Now, replace mass with another mass. i.e., four times the initial mass (as given)

If in case, the meter stick is to be at balanced form, then the acting torques sum would be zero. So,

$4 m g(x)+(m g)(x-50 c m)=0$

$4 m g x+m g x-50 m g=0$

Taking out ‘mg’ as common and we get

$5 x=50$

$x=\frac{50}{5}=10 \mathrm{cm}$

Hence, the stick should be pivoted at a distance of,

$x^{\prime}=100 \mathrm{cm}-10 \mathrm{cm}=10 \mathrm{cm}$

So, the stick should be pivoted at a distance of 10 cm from the free end.

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2 years ago

A 4.00-kg mass is attached to a very light ideal spring hanging vertically and hangs at rest in the equilibrium position. The sp

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$-0.02 = 0.02cos(0 + \phi) => \phi = \pi$

2. Finding time t at position y = 1 cm:

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3. Find velocity v at time t from equation 2:

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Answer:

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1 year ago