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3 years ago

Which scenarios are examples of physical changes? Select three options

Physics

1 answer:

pashok25 [27]3 years ago

4 0

Answer:

A kid becoming an adult

A leg becoming bruised

A person's blood pressure raising because they are running

need a picture to answer specific questions.

Explanation:

All of these are physical changes. Hope that this helps you and have a great day :)

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An object with a mass of 4.91 kg rests on a plane inclined 42.34 ° from horizontal. What is the component of the weight force th

12345 [234]

the perpendicular component will be = Wy

Wy = w * cos 42.34 = 48.11 N x cos 42.34 = 35.54 N

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1 year ago

Velocityis a vector quantity which has both magnitude and direction. Using complete sentences, describethe object's velocity. Co

mr_godi [17]

Answer:

Explanation:

A physical quantity which can be completely described by the magnitude and direction both are called vector quantities. For example, displacement, velocity, etc.

A physical quantity which can be completely explained by the magnitude only is called scalar quantity. For example, mass, time, etc.

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3 years ago

Two uniform, solid cylinders of radius R and total mass M are connected along their common axis by a short, light rod and rest o

sveta [45]

Explanation:

A) To prove the motion of the center of mass of the cylinders is simple harmonic:

System diagram for given situation is shown in attached Fig. 1

We can prove the motion of the center of mass of the cylinders is simple harmonic if

$a_{x} = -\omega^{2} x$

where aₓ is acceleration when attached cylinders move in horizontal direction:

<h3>PROOF:</h3>

rotational inertia for cylinders is given as:

$I=\frac{1}{2}MR^{2}$ -----(1)

Newton's second law for angular motion is:

∑τ = Iα ------(2)

For linear motion in horizontal direction it is:

∑Fₓ = Maₓ ------ (3)

By definition of torque:

τ = RF --------(4)

Put (4) and (1) in (2)

$RF=\frac{1}{2}MR^{2}\alpha$

from Fig 3 it can be seen that fs is force by which the cylinders roll without slipping as they oscillate

So above equation becomes

$f_{s}=\frac{1}{2}MR\alpha$ ------ (5)

As angular acceleration is related to linear by:

$a= R\alpha$

Eq (5) becomes

$f_{s}=\frac{1}{2}Ma_{x}$ ---- (6)

aₓ shows displacement in horizontal direction

From (3)

∑Fₓ = Maₓ

Fₓ is sum of fs and restoring force that spring exerts:

$\sum F_{x} = f_{s} - kx$ ----(7)

Put (7) in (3)

$f_{s} - kx = Ma_{x}$ [/tex] -----(8)

Using (6) in (8)

$\frac{1}{2}Ma_{x} - kx =Ma_{x}$

$a_{x} = \frac{2k}{3M} x$ --- (9)

For spring mass system

$a= -\omega^{2} x$ ----- (10)

Equating (9) and (10)

$\omega^{2} = \frac{2k}{3M}$

$\omega = \sqrt{ \frac{2k}{3M}}$

then (9) becomes

$a_{x} = - \omega^{2}x$

(The minus sign says that x and aₓ have opposite directions as shown in fig 3)

This proves that the motion of the center of mass of the cylinders is simple harmonic.

<h3 /><h3>B) Time Period</h3>

Time period is related to angular frequency as:

$T=\frac{2\pi }{\omega}$

$T = 2\pi \sqrt{\frac{3M}{2k}$

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3 years ago

Which one of the following statements about sulfuric acid is correct?

kherson [118]

The answer is C. Sulfuric Acid is dangerous to living organism

Direct contact with your skin and it will cause Chemical Burns , Direct contact with your eyes and it could cause a permanent Blindness.

This chemical also suck the water out of everything, so you can guess what will happen if it get into your body.

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3 years ago

if the time is taken to bring a ball to rest from a certain velocity 'v'. is reduced to half, what will be the change in the val

777dan777 [17]

The answer is C) rate of change of momentum. The answer is not initial or final momentum as the start and end points are not changing. On the other hand, the time it takes for the ball to change velocity is. This change relates to the change of momentum. Hope this helped :))

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3 years ago