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3 years ago

Calculate the potential energy of a rock that has a 45 kg mass and is sitting

Physics

1 answer:

Montano1993 [528]3 years ago

6 0

Answer:

P.E = 13230 J

Explanation:

Given,

The mass of the rock, m = 45 Kg

The rock is sitting at a height from the ground, h = 30 m

The acceleration due to gravity, g = 9.8 m/s²

The potential energy of the body is given by the formula,

P.E = mgh joules

Substituting the given values in the above equation

P.E = 45 x 9.8 x 30

= 13230 J

Hence, the potential energy of the rock is P.E = 13230 J

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The resistivity of gold is at room temperature. A gold wire that is 0.9 mm in diameter and 14 cm long carries a current of 940 m

IgorC [24]

Answer:

0.0360531138247 V/m

Explanation:

$\rho$ = Resistivity of gold = $2.44\times 10^{-8}\ \Omega .m$ (General value)

I = Current = 940 mA

d = Diameter = 0.9 mm

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

E = Electric field

Resistivity is given by

$\rho=\dfrac{EA}{I}\\\Rightarrow E=\dfrac{\rho I}{A}\\\Rightarrow E=\dfrac{2.44\times 10^{-8}\times 940\times 10^{-3}}{\dfrac{\pi}{4}(0.9\times 10^{-3})^2}\\\Rightarrow E=0.0360531138247\ V/m$

The electric field in the wire is 0.0360531138247 V/m

6 0

3 years ago

Read 2 more answers

The area of a rectangular park is 4 mi^2. The park has a width that is equal to "w", and a length that is 3 mi longer than the w

goldfiish [28.3K]

Answer:

l= 4 mi : width of the park

w= 1 mi : length of the park

Explanation:

Formula to find the area of the rectangle:

A= w*l Formula(1)

Where,

A is the area of the rectangle in mi²

w is the width of the rectangle in mi

l is the width of the rectangle in mi

Known data

A = 4 mi²

l = (w+3)mi Equation (1)

Problem development

We replace the data in the formula (1)

A= w*l

4 = w* (w+3)

4= w²+3w

w²+3w-4= 0

We factor the equation:

We look for two numbers whose sum is 3 and whose multiplication is -4

(w-1)(w+4) = 0 Equation (2)

The values of w for which the equation (2) is zero are:

w = 1 and w = -4

We take the positive value w = 1 because w is a dimension and cannot be negative.

w = 1 mi :width of the park

We replace w = 1 mi in the equation (1) to calculate the length of the park:

l= (w+3) mi

l= ( 1+3) mi

l= 4 mi

8 0

3 years ago

How do you determine the wattage capacity needed by a power supply?

Lady bird [3.3K]

We could use the formula for the Power supply in order to find the wattage capacity and it would be:

P = V²/R or P = V * I

Hope this helps!

6 0

2 years ago

The current that flows from and back to the power supply in a parallel circuit is called __________ current.

blagie [28]

Answer:

mainline current

Explanation:

Current that flows from and back to the power supply in a parallel circuit. Fuse. A type of circuit protection device.

6 0

2 years ago

Gravel is being dumped from a conveyor belt at a rate of 10 ft3/min, and its coarseness is such that it forms a pile in the shap

AURORKA [14]

Answer: The height of the pile increasing is increasing at $0.16\frac{ft}{min}$

Explanation:

Given

Rate at which gravel is being dumped , $\frac{\mathrm{d} V}{\mathrm{d} t}=10\frac{ft^{3}}{min}$

=>Rate of increase of volume of cone= $\frac{\mathrm{d} V}{\mathrm{d} t}=10\frac{ft^{3}}{min}$

If height of the cone at any instant is h then the diameter of cone is also h

Volume of cone , $V=\frac{\pi r^{2}h}{3}=\frac{\pi h^{3}}{4\times 3}=\frac{\pi h^{3}}{12}$

Now differentiate both sides w.r.t time(t)

$\frac{\mathrm{d} V}{\mathrm{d} t}=\frac{\pi h^{2}}{4}\frac{\mathrm{d} h}{\mathrm{d} t}$

Therefore at h = 9 ft

$10=\frac{\pi \times 9^{2}}{4}\times \frac{\mathrm{d} h}{\mathrm{d} t}$

=> $\frac{\mathrm{d} h}{\mathrm{d} t}=0.16\frac{ft}{min}$

Thus the height of the pile increasing is increasing at $0.16\frac{ft}{min}$

6 0

3 years ago