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3 years ago

a crane does 9,500 J of work to lift a crate straight up using a force of 125 N. how high does the crane lift the crate?

Physics

1 answer:

Lina20 [59]3 years ago

7 0

Answer:

The crane lifts the crate up to 76 m high

Explanation:

Work Done by a Force

The work done by a force of magnitude F that displaces an object by a distance y is given by

$W=F.y$

We know a crane does a work of 9,500 Joule to lift a crate and is using a force of 125 Nw.

The above equation can be solved to know the value of y in terms of the work and the force:

$\displaystyle y=\frac{W}{F}$

Plugging in the given values

$\displaystyle y=\frac{9,500}{125}$

$y=76\ m$

The crane lifts the crate up to 76 m high

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3 years ago

Consider a 20 cm thick granite wall with a thermal conductivity of 2.79 W/m·K. The temperature of the left surface is held const

kozerog [31]

Answer:

The right wall surface temperature and heat flux through the wall is 35.5°C and 202.3W/m²

Explanation:

Thickness of the wall is L= 20cm = 0.2m

Thermal conductivity of the wall is K = 2.79 W/m·K

Temperature at the left side surface is T₁ = 50°C

Temperature of the air is T = 22°C

Convection heat transfer coefficient is h = 15 W/m2·K

Heat conduction process through wall is equal to the heat convection process so

$Q_{conduction} = Q_{convection}$

Expression for the heat conduction process is

$Q_{conduction} = \frac{K(T_1 - T)}{L}$

Expression for the heat convection process is

$Q_{convection} = h(T_2 - T)$

Substitute the expressions of conduction and convection in equation above

$Q_{conduction} = Q_{convection}$

$\frac{K(T_1 - T_2)}{L} = h(T_2 - T)$

Substitute the values in above equation

$\frac{2.79(50- T_2)}{0.2} = 15(T_2 - 22)\\\\T_2 = 35.5^\circC$

Now heat flux through the wall can be calculated as

$q_{flux} = Q_{conduction} \\\\q_{flux} = \frac{K(T_1 - T_2)}{L}\\\\q_{flux} = \frac{2.79(50 - 35.5)}{0.2}\\\\q_{flux} = 202.3W/m^2$

Thus, the right wall surface temperature and heat flux through the wall is 35.5°C and 202.3W/m²

6 0

3 years ago

What speed must an electron have if its momentum is to be the same as that of an x-ray photon with a wavelength of 0.30?

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The momentum of the x-ray photon is p = h/lambda . Lambda is the wavelength (0.30nm=3x10^(-9)m) and h is Planck's constant,(h=6.62607004 × 10-34 m2 kg / s).The momentum is: 2.2 x 10^(-25).

The momentum can be calculated also as: p=mv, where m is the mass of the electron and v is the speed.

So v=p/m,p is known,and also the mass of the electron (m=9.10938356 × 10-31 kilograms).

v=2.2 x 10^(-25)/9.10938356 × 10-31 kilograms=0.24 x 10^6 m/s

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3 years ago

tamaranim1 [39]

the friction force provided by the brakes is 30000 N.

<h3>What is friction force?</h3>

Friction force is the force that opposes the motion between two bodies in contact.

To calculate the average friction force provided by the brakes, we apply the formula below.

Formula:

K.E = F'd............. Equation 1

Where:

K.E = Kinetic energy of the train
F' = Friction force provided by the brakes
d = distance

Make F' the subject of the equation

F' = K.E/d............ Equation 2

From the question,

Given:

K.E = 8.1×10⁶
d = 270 m

Substitute these values into equation 2

F' = (8.1 ×10⁶)/270
F' = 30000 N

Hence, the friction force provided by the brakes is 30000 N

Learn more about friction force here: brainly.com/question/13680415

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2 years ago

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Both verbs come from Olde English.
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For two weeks after the Full Moon, it's shrinking toward New.
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