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3 years ago

Energy and work are measured in

Physics

2 answers:

bekas [8.4K]3 years ago

5 0

Answer:

i'll help you bro

Explanation:

Advocard [28]3 years ago

5 0

Answer:

Energy and work are measured in Joule.

Hope it will help :)

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Answer:

Waves transfer energy, not motion

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2 years ago

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Which of these is part of the middle ear?

Tamiku [17]

The answer is D. The Ossicles

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3 years ago

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A ball is kicked from a location 7, 0, −8 (on the ground) with initial velocity −11, 19, −5 m/s. The ball's speed is low enough

Alja [10]

Answer:

$\vec{v} =$

Explanation:

given,

location of the ball ⟨7,0,−8⟩

initial velocity of the ball ⟨-11,19,−5⟩

time = 0.4 s

speed of the ball = ?

using Momentum Principle

change in momentum = Force x time

$m \vec{v} - m \vec{u}= \vec{F}\times \Delta t$

$\vec{v} =\vec{u} + \dfrac{\vec{F}}{m}\times \Delta t$

Net force acting in this case will be equal to force due to gravity because air resistance is negligible.

F_net = F_g = ⟨0 ,-9.8 m , 0⟩

now,

$\vec{v} = + \dfrac{}{m}\times (0.4-0)$

$\vec{v} = +$

$\vec{v} =$

hence, the velocity of the ball 0.4 s after being kicked is equal to $\vec{v} =$

5 0

3 years ago

A conducting wire is quadrupled in length and tripled in diameter.

aivan3 [116]

Answer:

Its resistance decreases

Explanation:

The resistance of a wire is directly proportional to the length of the wire and inversely proportional to the cross sectional area of the wire.

Mathematically,

R1 =¶L1/A1... (1)

R1= ¶L1/{Πd²/4}

R1= 4¶L1/Πd²

where;

¶ is the constant of proportionality which is the resistivity of the material

L is the length of the wire

A is the cross sectional area

A1 = Πd²/4

If the length is quadrupled and its diameter tripled

The new length L2 will be 4L1

New area A2 = Π(3d)²/4 = 9Πd²/4

The resistance will become

R2 = ¶(4L1)/{9Πd²/4}

R2 = 4¶L1×4/9Πd²

R2 = 16¶L1/9Πd²... (2)

R2/R1 = 16¶L1/9Πd²÷4¶L1/Πd²

R2/R1 = 16¶L1/9Πd²×Πd²/4¶L1

R2/R1 = 16/9×1/4

R2/R1 = 16/36

R2/R1 = 4/9

R2 = 4/9R1

This shows that the resistance of the wire decreases

7 0

3 years ago

Read 2 more answers

If you triple the speed from 20km/h to 60km/h, by what factor does the KE increase?

sertanlavr [38]

Answer:

<em>The kinetic energy increases by a factor of 9 </em>

Explanation:

<u>Kinetic Energy </u>

It's the energy related to the speed of an object and is calculated by the formula

$\displaystyle K=\frac{mv^2}{2}$

Let's suppose the initial speed of the mass is $v_o$ , then the kinetic energy is

$\displaystyle K_o=\frac{mv_o^2}{2}$

Now the speed will triple, i.e. $v_1=3v_o$ . The new kinetic energy is

$\displaystyle K_1=\frac{mv_1^2}{2}$

$\displaystyle K_1=\frac{m(3v_o)^2}{2}$

$\displaystyle K_1=9\frac{mv_o^2}{2}$

Thus

$K_1=9K_o$

The kinetic energy increases by a factor of 9

Let's check with numbers: $v_o=20,\ v_1=60$

$\displaystyle K_o=\frac{m20^2}{2}=200m$

$\displaystyle K_1=\frac{m60^2}{2}=1800m$

The relation is

$\displaystyle \frac{K_1}{K_o}=9$

The new kinetic energy is nine times the initial kinetic energy.

5 0

3 years ago