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2 years ago

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a closed systems internal energy changes by 178 j as a result of being heated with 658 j of energy. the energy used to do work b

y the system is j

1 answer:

Akimi4 [234]2 years ago

7 0

<h3><u>Answer;</u></h3>

= 480 Joules

<h3><u>Explanation;</u></h3>

We use the formula, Q - W = ΔU

Where, Q = Heat transferred to the system

W = Work done by the system

ΔU = Change of internal energy.

As per the question, Q = 658 J

ΔU = 178 J

Thus, W = Q - ΔU = (658 - 178) J = 480 J.

The energy used to do work by the system is 480 J.

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A steel cable 1.25 in. in diameter and 50 ft long is to lift a 20-ton load without permanently deforming. What is the length of

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Answer:

50.0543248872 ft

Explanation:

F = Load = 20 ton = $20\times 2000\ lb$

d = Diameter = 1.25 in

$L_1$ = Initial length = 50 ft

$L_2$ = Final length

A = Area = $\dfrac{\pi}{4}d^2$

Y = Young's modulus = $30\times 10^6\ psi$

Young's modulus is given by

$Y=\dfrac{FL}{A\Delta L}\\\Rightarrow Y=\dfrac{FL_1}{\dfrac{\pi}{4}d^2(L_2-L_1)}\\\Rightarrow L_2=\dfrac{4FL_1}{Y\pi d^2}+L_1\\\Rightarrow L_2=\dfrac{4\times 40000\times 50}{30\times 10^6\times \pi\times 1.25^2}+50\\\Rightarrow L_2=50.0543248872\ ft$

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2 years ago

Two thermometers are calibrated, one in degrees Celsius and the other in degrees Fahrenheit.

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Answer:

The temperature is 233.15 K

Explanation:

Recall the formula to convert degree Celsius (C) into Fahrenheit (F):

$\frac{9}{5} C+32=F$

So if we want the value of degree C to be the same as the value of the degree F, we want the following: C = F

which replacing F with C on the right hand side of the equation above, allows us to solve for C:

$\frac{9}{5} C+32=F\\\frac{9}{5} C+32=C\\\frac{9}{5} C-\frac{5}{5} C =-32\\\frac{4}{5} C==32\\C= \frac{-32\,*\,5}{4} \\C=-40$

This means that -40°C = -40°F

And this temperature in Kelvin is:

-40°C + 273.15 = 233.15 K

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2 years ago

High-speed stroboscopic photographs show that the head of a 200 g golf club is traveling at 43.7 m/s just before it strikes a 45

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Answer:

41.27m/s

Explanation:

According to law of conservation of momentum

m1u1+m2u2 = (m1+m2)v

m1 and m2 are the masses

u1 and u2 are the initial velocities

v is the velocity after impact

Given

m1 = 0.2kg

u1 = 43.7m/s

m2 = 45.9g = 0.0459kg

u2 = 30.7m/s

Required

Velocity after impact v

Substitute the given parameters into the formula

0.2(43.7)+0.0459(30.7) = (0.2+0.0459)v

8.74+1.409 = 0.2459v

10.149 = 0.2459v

v = 10.149/0.2459

v = 41.27m/s

Hence the speed of the golf ball immediately after impact is 41.27m/s

8 0

2 years ago

The force on a wire is a maximum of6.71 10-2 N when placed between the pole faces of a magnet.The current flows horizontally to

Taya2010 [7]

Answer:

B. i=2.79A

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F=iL x B

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C) Now the length of the wire that feels B is

$L=\frac{0.15m}{cos(10\°)}=0.152m$

and the force will be (by taking the degrees between the magnetic field vector and current vector as 80°)

$F=iLBsin(\alpha)\\F=(2.79A)(0.152m)(0.16T)(sin(80\°))=0.066N$

I hope this is useful for you

regards

8 0

2 years ago

A firecracker is thrown downward from a height of 2.75m above the ground, with a speed of 3.15m/s. Ignore air resistance, determ

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Here in this question as we can see there is no air friction so we can use the principle of energy conservation

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$mgh_1 + \frac{1}{2}mv_i^2 = mgh_2 + \frac{1}{2}mv_f^2$

now here we know that

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$v_f = 5.23 m/s$

now plug in all values in above equation

$mg*2.75 + 0 = mgh + \frac{1}{2}m(5.23)^2$

divide whole equation by mass "m"

$9.8*2.75 = 9.8*h + \frac{1}{2}*27.35$

$9.8*h = 13.27$

$h = 1.35 m$

so height of the ball from ground will be 1.35 m

4 0

2 years ago