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2 years ago

A 9-kg body has three times the kinetic energy of an 4-kg body. Calculate the ratio of the speeds of these bodies.

Physics

1 answer:

Neko [114]2 years ago

3 0

Answer:

speed 9/speed 4 = 2sqrt3 / 3

Explanation:

KE = 1/2 m v^2

for 9 kg = 3 * the 4 kg 1/2 (9)va^2 = <u> 3</u>* 1/2 (4) vb^2

va^2 / vb^2 = 3* 1/2 (4) / (1/2 *9)

6 / 4.5

va / vb = sqrt (6/4.5) = 2sqrt3 /3

ratio of the 9 speed to the speed of the 4 is 2 sqrt 3 /3

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As shown in the figure below, a bullet is fired at and passes through a piece of target paper suspended by a massless string. Th

NikAS [45]

Answer:

M = 0.730*m

V = 0.663*v

Explanation:

Data Given:

$v_{bullet, initial} = v\\v_{bullet, final} = 0.516*v\\v_{paper, initial} = 0\\v_{paper, final} = V\\mass_{bullet} = m\\mass_{paper} = M\\Loss Ek = 0.413 Ek$

Conservation of Momentum:

$P_{initial} = P_{final}\\m*v_{i} = m*0.516v_{i} + M*V\\0.484m*v_{i} = M*V .... Eq1$

Energy Balance:

$\frac{1}{2}*m*v^2_{i} = \frac{1}{2}*m*(0.516v_{i})^2 + \frac{1}{2}*M*V^2 + 0.413*\frac{1}{2}*m*v^2_{i}\\\\0.320744*m*v^2_{i} = M*V^2\\\\M = \frac{0.320744*m*v^2_{i} }{V^2} ....... Eq 2$

Substitute Eq 2 into Eq 1

$0.484*m*v_{i} = \frac{0.320744*m*v^2_{i} }{V^2} *V \\0.484 = 0.320744*\frac{v_{i} }{V} \\\\V = 0.663*v_{i}$

Using Eq 1

$0.484m*v_{i} = M* 0.663v_{i}\\\\M = 0.730*m$

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3 years ago

2 Magnetism comes from the word

AysviL [449]

Answer:

A Magnesia

Explanation:

The word magnetism comes from the word Magnesia, which is the name for a region in Asia Minor, where fragments of Fe3O4 ore (magnetite) were found, which attracts other metal objects.

Magnetism is a physical phenomenon by which we describe the attractive or repulsive force between materials.

This phenomenon has been known for thousands of years.

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2 years ago

The robot arm is elevating and extending simultaneously. At a given instant, θ = 30°, ˙ θ = 10 deg / s = constant θ˙=10 deg/s=co

motikmotik

Explanation:

The position vector r:

$\overrightarrow{r(t)}=lcos\theta\hat{i}+lsin\theta\hat{j}$

The velocity vector v:

$\overrightarrow{v(t)}=\overrightarrow{\frac{dr}{dt}}=\dot{l}cos\theta-lsin\theta\dot{\theta}\hat{i}+\dot{l}sin\theta+lcos\theta\dot{\theta}\hat{j}$

The acceleration vector a:

$\overrightarrow{a(t)}}=cos\theta(\ddot{l}-l\dot{\theta}^2)-sin\theta(2\dot{l}\dot{\theta}+l\ddot{\theta})\hat{i}+cos\theta(2\dot{l}\dot{\theta}+l\ddot{\theta})+sin\theta(\ddot{l}-l\dot{\theta}^2)\hat{j}$

$\overrightarrow{v(t)}=0.13\hat{i}+0.18\hat{j}$

$\overrightarrow{a(t)}}=-0.3\hat{i}-0.1\hat{j}$

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2 years ago

The nervous system has two distinct branches. They are the:

Troyanec [42]

Answer:

central nervous system

peripheral nervous system

Explanation:

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Anni [7]

It is overhead at the equator, it is because the sun ray’s will be moving vertically as this will be directed at the equator. It is because if it moves vertically, it will hit or overhead the equator and this usually happens in spring and fall.

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3 years ago