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2 years ago

Someone help me please i need to finish this

Physics

2 answers:

Ilya [14]2 years ago

8 0

Answer:

D. A zinc Zn contains 30 protons inside the nucleus and 30 electron outside the nucleus

gavmur [86]2 years ago

5 0

Answer:

the last option is correct

Explanation:

see I won't explain all the points but will tell you the concept being used.

protons and neutrons are inside the nucleus in an atom while the electrons are outside the nucleus.

the mass number of an atom is equal to the sum of number of electrons and neutrons in an atom
atomic number is equal to the number of electrons which is equal to the number of protons in an atom
no. of electrons/ protons is always less than that of neutrons and they're almost equal( a large difference ain't obtained between the number of electrons and that of neutrons.

since, the rest of the options are violating the above rules they're incorrect

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At high noon, the sun delivers 1150 w to each square meter of a blacktop road. if the hot asphalt loses energy only by radiation

Pie

Stephen`s Law:
P = (Sigma) · A · e · T^4
P in = P out
e = 1 for blacktop;
1150 W = (Sigma) · T^4
(Sigma) = 5.669 · 10 ^(-8) W/m²K^4
T^4 = 1150 : ( 5.669 · 10^(-8) )
T^4 = 202.875 · 10^8
$T = \sqrt[4]{202.857 * 10 ^{8} }$
T = 3.774 · 10² = 377.4 K
Answer: Equilibrium temperature is 377.4 K.

3 0

2 years ago

A concrete piling of 50 kg is suspended from a steel wire of diameter 1.0 mm and length 11.2 m. How much will the wire stretch?

pentagon [3]

Explanation:

It is given that,

Mass of concrete pilling, m = 50 kg

Diameter of wire, d = 1 mm

Radius of wire, r = 0.0005 m

Length of wire, L = 11.2

Young modulus of steel, $Y=20\times 10^{10}\ N/m^2$

The young modulus of a wire is given by :

$Y=\dfrac{\dfrac{F}{A}}{\dfrac{\Delta L}{L}}$

$Y=\dfrac{F.L}{A\Delta L}$

$\Delta L=\dfrac{F.L}{A.Y}$

$\Delta L=\dfrac{50\ kg\times 9.8\ m/s^2\times 11.2\ m}{\pi (0.0005\ m)^2\times 20\times 10^{10}\ N/m^2}$

$\Delta L=0.034\ m$

So, the wire will stretch 0.034 meters. Hence, this is the required solution.

8 0

3 years ago

A roller coaster car of mass m = 300 kg is released from rest at the top of a 60 m high hill (position A), and rolls with a negl

Triss [41]

Answer:

The principle of conservation of energy and angular momentum

Explanation:

At point A, the car experienced maximum of potential energy

As it moves down the hill, the potential energy decreases while the kinetic energy increases.

The maximum kinetic energy of the car is needed for the attainment of enough centripetal force to help the car move through the loop without falling .

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2 years ago

"The International Space Station (ISS) orbits at a distance of 350 km above the surface of the Earth. (a) Determine the gravitat

vagabundo [1.1K]

Answer:

(a) g = 8.82158145 $m/s^2$ .

(b) 7699.990192m/s.

Explanation:

(a) Strength of gravitational field 'g' by definition is

$g = \frac{M_{(earth)} }{r^2} G$ , here G is Gravitational Constant, and r is distance from center of earth, all the values will remain same except r which will be radius of earth + altitude at which ISS is in orbit.

r = 6721,000 meters, putting this value in above equation gives g = 8.82158145 $m/s^2$ .

(b) We have to essentially calculate centripetal acceleration that equals new 'g'.

$a_{centripetal}=\frac{V^2}{r} =g$ here g is known, r is known and v is unknown.

plugging in r and g in above and solving for unknown gives V = 7699.990192m/s.

(c) S = vT, here T is time period or time required to complete one full revolution.

S = earth's circumfrence , V is calculated in (B) T is unknown.

solving for unknown gives T = 5484.3301s = 1.5234hours.

3 0

3 years ago

10. Josie and Trey were working on their physics project and both built catapults. Trey's catapult shot a ball

SVEN [57.7K]

Answer:

Josie's ball faster than T

3 0

1 year ago