An apple falls off a roof .It takes the apple 15.7 seconds to hit the floor . How far did the apple fall?

A child on a bridge throws a rock straight down to the water below. The point where the child released the rock is 82 m above th

eimsori [14]

Answer:

40 m/s

Explanation:

given,

height of the fall, h = 82 m

time taken to fall, t = 1.3 s

rock velocity, v = ?

acceleration due to gravity, g = 9.8 m/s²

rock is released initial velocity, u = 0 m/s

using equation of motion

v² = u² + 2 a s

v² = 0 + 2 x 9.8 x 82

v² = 1607.2

v = 40 m/s

hence, rock's velocity is equal to 40 m/s

6 0

3 years ago

Which of two factors influence the weight of an object due to gravitational pull?

Tresset [83]

The masses of the object and the planet it's on, and the distance between their centers.

7 0

3 years ago

Read 2 more answers

The direction of the force on a current-carrying wire in a magnetic field is

Bess [88]

Answer:

Explanation:

The forces acting on a conductor carrying current placed in a magnetic field is analysed using the Fleming's left hand rule.

The rule states that "If the fire finger, the middle finger and the thumb are held mutually perpendicular to one another in a magnetic field, the fore finger acts in the direction of the magnetic field, the middle finger acts on the direction of the current while the thumb acts in the direction of the force.

Based on the rule, it can be inferred this current carrying wire placed in the magnetic field acts perpendicular to the magnetic field and force acting on the wire.

6 0

3 years ago

Read 2 more answers

An avant-garde composer wants to use the Doppler effect in his new opera. As the soprano sings, he wants a large bat to fly towa

Allisa [31]

Answer:

v’= 9.74 m / s

Explanation:

The Doppler effect is due to the relative movement of the sound source and the receiver of the sound, in this case we must perform the exercise in two steps, the first to find the frequency that the bat hears and then the frequency that the audience hears that also It is sitting.

Frequency shift heard by the murciela, in case the source is still and the observer (bat) moves closer

f₁ ’= f₀ (v + v₀)/v

Frequency shift emitted by the speaker in the bat, in this case the source is moving away from the observer (public sitting) that is at rest

f₂’= f₁’ v/(v - vs)

Note that in this case the bat is observant in one case and emitter in the other, called its velocity v’

v’= vo = vs

Let's replace

f₂’= f₀ (v + v’)/v v/(v -v ’)

f₂’= f₀ (v + v’) / (v -v ’)

(v –v’ ) f₂’ / f₀ = v + v ’

v’ (1+ f₂’ /f₀) = v (f₂’/fo - 1)

v’ (1 + 1.059) = 340 (1.059 - 1)

v’= 20.06 / 2.059

v’= 9.74 m / s

6 0

3 years ago

Find the electron and hole concentrations and fermi level in silicon at 300 k for boron

gogolik [260]

To find the electron and hole concentrations and fermi levels in silicon at 300 k for boron, fermi level is 9.3 x $10^4 cm^-3$ .

<h3>Calculation and Explanation</h3>

Ionization energy for boron in Si, 0.045 eV

Fermi level in silicon,

300 K at $10^{15} cm^{-3}$ (Boron atoms)

All boron impurities are ionized, 300K

Electron, hole concentrations and Fermi levels is found out,

The value of Na = $10^{15} cm^{-3}$

np = $\frac{ni^2}{nA}$

np = $\frac{(9.65 x 10^9)^2}{10^15}$

np= 9.3 x $10^4 cm^-3$

Fermi level is calculated,

Ef - Ev = kT ln(NV/ND)

value of kT = 0.0259 eV (300° K)

So, substitution the values

Ef - Ev = kT ln(NV/ND)

Ef - Ev = 0.0259ln (2.66 x $10^{19} / 10^{15}$ )

Ef - Ev = 0.0259ln (26600)

Ef - Ev = 0.0259 x 10.18

Ef - Ev = 0.263 eV

What is ionization energy?

Ionization energy, also known as ionization energy (IE) or ionization energy (British English spelling), is the minimal amount of energy needed to free the most loosely bonded electron from an isolated gaseous atom, positive ion, or molecule in physics and chemistry.

To know more about ionization energy, visit:

brainly.com/question/16243729

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4 0

1 year ago