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3 years ago

Work is required to lift a barbell. How many times more work is required to lift the barbell three times as high

Physics

1 answer:

bixtya [17]3 years ago

7 0

The work times 3 .
N.B: Work = Force x Distance
and in here the distance increased to 3.

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What is the arrow pointing to?

e-lub [12.9K]

Answer: A. Spine

Hope this helps.

7 0

3 years ago

How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 3.33×10−21 n

qwelly [4]

Answer:

The number of excess electrons on each sphere is 759

Explanation:

Given that,

distance , d = 20 cm

= 0.20 m

let the number of electrons is n

Electric force (F) = k × (n × e)² /d²

3.33 × $10^{-21}$ = 9 × $10^{9}$ × (n × 1.602 × $10^{-19}$ )² /0.2²

solving for n

n = 759

4 0

3 years ago

The heat flux for a given wall is in the x-direction and given as q^n = 11 W/m^2, the walls thermal conductivity is 1.7 W/mK and

MrMuchimi

Answer:

$\frac{dT}{dx} = 6.47 ^oC/m$

Also as we can see the equation that heat flux directly depends on the temperature gradient so more is the temperature gradient then more will be the heat flux.

For positive temperature gradient the heat will flow outwards while for negative temperature gradient the heat will flow inwards

Explanation:

As we know that heat flux is given by the formula

$q^n = K\frac{dT}{dx}$

here we know that

K = thermal conductivity

$\frac{dT}{dx}$ = temperature gradient

now we know that

$q^n = 11 W/m^2$

also we know that

K = 1.7 W/mK

now we have

$11 = 1.7 \frac{dT}{dx}$

so temperature gradient is given as

$\frac{dT}{dx} = \frac{11}{1.7} = 6.47 K/m$

also in other unit it will be same

$\frac{dT}{dx} = 6.47 ^oC/m$

Also as we can see the equation that heat flux directly depends on the temperature gradient so more is the temperature gradient then more will be the heat flux.

For positive temperature gradient the heat will flow outwards while for negative temperature gradient the heat will flow inwards

5 0

3 years ago

While you are looking at the image of your feet in a plane mirror, you see a scratch in the glass. What is the approximate heigh

Montano1993 [528]

Answer:

1.75 / 2 = 0.875 m

Explanation:

Provided the mirror is vertical and you are standing upright.

It could be most any altitude if the mirror is allowed any orientation.

3 0

3 years ago

Using the image, explain what information you are given and what you could solve for. Derive an equation that solves for the max

mezya [45]

Answer:

h = (v₀²sin²θ)/2g

R = (v₀²sin2θ)/g

Explanation:

general equation is s = s₀ + v₀t + ½at²

if the firing point is origin and UP and RIGHT are positive directions, and if we ignore air resistance.

In the vertical direction, and remembering that gravity opposes the initial vertical velocity, the equation becomes

y = 0 + (v₀sinθ)t - ½(g)t²

y = (v₀sinθ)t - ½(g)t²

at maximum height h, vertical velocity is zero. The initial vertical velocity is reduced to zero in a time of

t = (v₀sinθ)/g

entering this value into our equation for y

h = (v₀sinθ)(v₀sinθ)/g - ½(g)((v₀sinθ)/g)²

h = (v₀²sin²θ)/g - ½(g)(v₀²sin²θ)/g²

h = (v₀²sin²θ)/g - ½(v₀²sin²θ)/g

h = (v₀²sin²θ)/2g

In the horizontal the equation becomes

x = 0 + (v₀cosθ)t + ½(0)t²

x = (v₀cosθ)t

As it will take as long to fall as it took the projectile to rise to the a•pex.

R = (v₀cosθ)(2)((v₀sinθ)/g)

R = 2(v₀²cosθsinθ)/g

trig identity sin2θ = 2cosθsinθ

R = (v₀²sin2θ)/g

The algorithm thinks the word "a•pex" is a swear word so I have to write it like I have... What an a•pex

8 0

3 years ago