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2 years ago

A pump is to lift 18 kg of water per minute tthrough a height of 3.6 m. what output rating (watts) should the pump have?

1 answer:

7 0

Given: Mass m = 18 Kg; Height h = 3.6 m; Time t = 60 s

Required: Power output in unit of Watts

Formula: P = mgh/t

P = (18 Kg)(9.8 m/s²)(3.6 m)/60 s

P = 10.58 J/s or Watts

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You are given three pieces of wire that have different shapes (dimensions). You connect each piece of wire separately to a batte

VikaD [51]

Answer:

$R_3 < R_1 < R_2$

Explanation:

The resistance of a wire is given by:

$R=\frac{\rho L}{A}$

where

$\rho$ is the resistivity of the material

L is the length of the wire

A is the cross-sectional area of the wire

1) The first wire has length L and cross-sectional area A. So, its resistance is:

$R_1=\frac{\rho L}{A}$

2) The second wire has length twice the first one: 2L, and same thickness, A. So its resistance is

$R_2=\frac{2\rho L}{A}$

3) The third wire has length L (as the first one), but twice cross sectional area, 2A. So, its resistance is

$R_3=\frac{\rho L}{2A}$

By comparing the three expressions, we find

$R_3 < R_1 < R_2$

So, this is the ranking of the wire from most current (least resistance) to least current (most resistance).

5 0

2 years ago

If 27 J of work are needed to stretch a spring from 15 cm to 21 cm and 45 J are needed to stretch it from 21 cm to 27 cm, what i

kupik [55]

Answer:

9 cm.

Explanation:

The energy used for stretch the spring from $15 cm$ to $21 cm$ will be , $E_{1}=27J$

The energy used for stretch the spring from $21 cm$ to $27 cm$ will be , $E_{2}=45J$

using the energy of spring formula ,we find that

$27 = \frac{1}{2}K((21-L^{2})-(15-L^{2}))$

$45 = \frac{1}{2}K((27-L^{2})-(21-L^{2}))$

Dividing both the equation will get,

$\frac{3}{5}=\frac{(21-L)^{2}-(15-L)^{2}}{(27-L)^{2}-(21-L)^{2}}\\5((21-L)^{2}-(15-L)^{2})=3((27-L)^{2}-(21-L)^{2})\\3(729 - 54L + L^{2}- 441 + 42L - L^{2} ) = 5(441 - 42L + L^{2} - 225 + 30L - L^{2} )\\3(288 - 12L) = 5(216 - 12L)\\24L = 216\\L = 9 cm$

Therefore, the natural length of the spring is, 9 cm.

4 0

3 years ago

For each of the following, describe the relationship as directly or inversely proportional:

Maksim231197 [3]

The relationships can best be described as follows:
As frequency increases, wavelength decreases. The greater the energy, the larger the frequency and the shorter (smaller) the wavelength. 

a) wavelength vs. frequency = inversely proportional
b) wavelength vs. energy = inversely proportional
c) frequency vs. energy = directly proportional

Hope this answers the questions. Have a nice day. Feel free to ask more questions.

7 0

3 years ago

If you weigh 690 N on the earth, what would be your weight on the surface of a neutron star that has the same mass as our sun an

lana [24]

Answer:

Explanation:

Given that,

Mass of star M(star) = 1.99×10^30kg

Gravitational constant G

G = 6.67×10^−11 N⋅m²/kg²

Diameter d = 25km

d = 25,000m

R = d/2 = 25,000/2

R = 12,500m

Weight w = 690N

Then, the person mass which is constant can be determined using

W =mg

m = W/g

m = 690/9.81

m = 70.34kg

The acceleration due to gravity on the surface of the neutron star is can be determined using

g(star) = GM(star)/R²

g(star) = 6.67×10^-11 × 1.99×10^30 / 12500²

g (star) = 8.49 × 10¹¹ m/s²

Then, the person weight on neutron star is

W = mg

Mass is constant, m = 70.34kg

W = 70.34 × 8.49 × 10¹¹

W = 5.98 × 10¹³ N

The weight of the person on neutron star is 5.98 × 10¹³ N

5 0

3 years ago

1.what is gravity?(in your own words)

olga_2 [115]

Answer:

1.Gravity is an invisible force that pulls objects toward each other

2.The suns gravity pulls the planet towards the sun which changes the straight line of direction into a curve

That keeps the planet moving in an orbit around the sun

hope it helped:)

8 0

2 years ago