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3 years ago

a Stone is dropped into a deep well and is heard to hit the water 3.41s after being dropped. determine the depth of the well

1 answer:

5 0

Using SUVAT

U = 0 m/s
A = g = 9.8 ms^-2
T = 3.41 s
S = ?

s = ut + 1/2at^2
s = (0)(3.41) + 1/2(9.8)(3.41^)
s = 1/2(9.8)(3.41^2)
s = 1/2(9.8)(11.6281)
s = 56.97769 m

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How much sweat (in ml) would you have to evaporate per hour to remove the same amount of heat a 90.0 w light bulb produces? (1w=

Sveta_85 [38]

1 W = 1 J/s
Therefore;
Total energy = 90*1*60*60 J = 324000 J = 324 kJ

Such an evaporation must take place at a temperature near the body temperature. Assuming a body temperature of 37°C at which heat of vaporization is approximately 2413.1 kJ/kg (again assuming sweet behaves like water).

Then,
mC = 324 kJ, where m = mass of sweet and C = heat of vaporization
Therefore,
m = 324/C = 324/2413.1 = 0.13427 kg

Density = m/v => volume = m/Density = 0.13427/1000 = 1.3427*10^-4 m^3
1 m^3 = 1000 liters
Then,
1.3427*10^-4 m^3 = 0.13427 liters of sweet = 134.27 ml

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3 years ago

The heater element of a 120 V toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. The resistivity of nichrome

Ksenya-84 [330]

Answer:

The power drawn by the toaster is closest to:

(A) 370 W

Explanation:

First we calculate the resistance of the nichrome wire (R).

$R=\frac{pL}{A} =\frac{pL}{\pi r^{2} } \\$

Where radious (r), resistance coefficient (p), and Length (L)

$r=\frac{0.48}{2} 10^{-3} m\\\\L=5.4 m\\p=1.3*10^{-3}\varOmega \\\\\\Replacing:\\\\R=\frac{1.3(10)^{-6} *5.4}{\pi* 0.24^{2} (10)^{-6}} =38.7940$

After replace the value in the ohm law power formula to obtain the power consumed:

$P=\frac{V^2}{R} =\frac{120^2}{38.7940} =371.191 Watts$

7 0

3 years ago

(a) Calculate the magnitude of the gravitational force exerted by Mars on a 80 kg human standing on the surface of Mars. (The ma

andrew11 [14]

Answer:

a) $F=1.044\times 10^9\ N$

b) $F'=1.044\times 10^9\ N$

c) $F_p=1.0672\times10^{-7}\ N$

d) Treat the humans as though they were points or uniform-density spheres.

Explanation:

Given:

mass of Mars, $M=6.4\times 10^{23}\ kg$

radius of the Mars, $r=3.4\times 10^{6}\ m$

mass of human, $m=80\ kg$

Gravitation force exerted by the Mars on the human body:

$F=G.\frac{M.m}{r^2}$

where:

$G=6.67 \times 10^{-11}\ m^3.kg^{-1}.s^{-2}$ = gravitational constant

$F=6.67\times10^{-11}\times \frac{6.4\times 10^{23}\times 80}{(3.4\times 10^{6})^2}$

$F=1.044\times 10^9\ N$

The magnitude of the gravitational force exerted by the human on Mars is equal to the force by the Mars on human.

$F'=F$

$F'=1.044\times 10^9\ N$

When a similar person of the same mass is standing at a distance of 4 meters:

$F_p=6.67\times10^{-11}\times \frac{80\times 80}{4}$

$F_p=1.0672\times10^{-7}\ N$

The gravitational constant is a universal value and it remains constant in the Universe and does not depends on the size of the mass.

Yes, we have to treat Mars as spherically symmetric so that its center of mass is at its geometric center.

Yes, we also have to ignore the effect of sun, but as asked in the question we have to calculate the gravitational force only due to one body on another specific body which does not brings sun into picture of the consideration.

4 0

3 years ago

Starting at (0,0) an object travels 36 meters north and then it covers 20 meters east. What is

Svetradugi [14.3K]

Answer:

Explanation:

Using the pythagoras theorem, the displacement is expressed as;

d² = x²+y²

y = 36m (north)

x = 20m east

Substitute;

d² = 36²+20²

d² = 1296+400

d² = 1696

d = √1696

d = 41.18m

For the direction;

theta = tan^-1(y/x)

theta = tan^-1(36/20)

theta = tan^-1(1.8)

theta = 60.95°

Hence the magnitude is 41.18m and the direction is 60.95°

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3 years ago

10. 1. Why is Newton's law of gravitation called universal law ?

Eduardwww [97]

Newtons law of gravitation is called the universal law of gravitation because it is applicable for all masses at all distances, independent of the medium.

6 0

2 years ago

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