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3 years ago

A rock of mass 200kg is dropped from a height of 200m. What is the Kinetic energy at:

Physics

2 answers:

const2013 [10]3 years ago

5 0

Da ansa is d ) jus befoo it hits da ground

Oksana_A [137]3 years ago

5 0

Explanation:

M=200kg

H=200m

for 0 second

now

ke=1/2mv^2

=1/2 .200.200/0

=40000/2

=20000 kgm/ s

for 2second

now

ke=1/2mv^2

=1/2.200.200/2

=40000/4

=10000 kgm/s

for 4second

now

ke= 1/2mv^2

=1/2.200.200/4

=40000/8

=5000 kgm/s

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A coil with an inductance of 2.3 H and a resistance of 14 Ω is suddenly connected to an ideal battery with ε = 100 V. At 0.13 s

klemol [59]

Given Information:

Resistance = R = 14 Ω

Inductance = L = 2.3 H

voltage = V = 100 V

time = t = 0.13 s

Required Information:

(a) energy is being stored in the magnetic field

(b) thermal energy is appearing in the resistance

Answer:

(a) energy is being stored in the magnetic field ≈ 219 watts

(b) thermal energy is appearing in the resistance ≈ 267 watts

Explanation:

The energy stored in the inductor is given by

$U = \frac{1}{2} Li^{2}$

The rate at which the energy is being stored in the inductor is given by

$\frac{dU}{dt} = Li\frac{di}{dt} \: \: \: \: eq. 1$

The current through the RL circuit is given by

$i = \frac{V}{R} (1-e^{-\frac{t}{ \tau} })$

Where τ is the the time constant and is given by

$\tau = \frac{L}{R}\\ \tau = \frac{2.3}{14}\\ \tau = 0.16$

$i = \frac{110}{14} (1-e^{-\frac{t}{ 0.16} })\\i = 7.86(1-e^{-6.25t})\\\frac{di}{dt} = 49.125e^{-6.25t}$

Therefore, eq. 1 becomes

$\frac{dU}{dt} = (2.3)(7.86(1-e^{-6.25t}))(49.125e^{-6.25t})$

At t = 0.13 seconds

$\frac{dU}{dt} = (2.3) (4.37) (21.8)\\\frac{dU}{dt} = 219.11 \: watts$

(b) thermal energy is appearing in the resistance

The thermal energy is given by

$P = i^{2}R\\P = (7.86(1-e^{-6.25t}))^{2} \cdot 14\\P = (4.37)^{2}\cdot 14\\P = 267.35 \: watts$

The energy delivered by battery is

$P = Vi\\P = 110\cdot 4.37\\P = 481 \: watts$

4 0

3 years ago

What is the difference between sodium atom and a sodium ion

ludmilkaskok [199]

Pretty much any element(in your case sodium) contain these properties.

Atoms can be an ion, but not all ions are atoms. The difference between an atom and an ion has to do with net electrical charge. An ion is a particle or collection of particles with a net positive or negative charge. ... A stable atom contains the same number of electrons as protons and no net charge

7 0

3 years ago

A portion of the atmosphere that becomes warmer than surrounding air will ____.

earnstyle [38]

A portion of the atmosphere that becomes warmer than surrounding air will expand and rise. The warmer atmosphere the more space between the molecules. Therefore, warmer atmosphere expands to allow more space for the molecules. Cool air on the other hand, contracts because the molecules in cool air need less space.

3 0

3 years ago

An engine absorbs 1749 J from a hot reservoir and expels 539 J to a cold reservoir in each cycle. a. What is the engine’s effici

Masja [62]

Answer:

a)η = 69.18 %

b)W= 1210 J

c)P=3967.21 W

Explanation:

Given that

Q₁ = 1749 J

Q₂ = 539 J

From first law of thermodynamics

Q₁ = Q₂ +W

W=Work out put

Q₂=Heat rejected to the cold reservoir

Q₁ =heat absorb by hot reservoir

W= Q₁- Q₂

W= 1210 J

The efficiency given as

$\eta=\dfrac{W}{Q_1}$

$\eta=\dfrac{1210}{1749}$

$\eta=0.6918$

η = 69.18 %

We know that rate of work done is known as power

$P=\dfrac{W}{t}$

$P=\dfrac{1210}{0.305}\ W$

P=3967.21 W

8 0

3 years ago

Technician A says a short to voltage may or may not blow a fuse and may or may not affect more than one circuit. Technician B sa

Tomtit [17]

Answer:

C. Both A and B

Explanation:

Fuses are rated by the amperage they can carry before heat melts the element. The fuse is ideal for protection against short circuits. Short circuits produce enough amperage to vaporize a fuse element and break connection in one cycle of a 60-cycle system.

Specifically, the voltage rating determines the ability of the fuse to suppress the internal arcing that occurs after a fuse link melts and an arc is produced.

6 0

3 years ago