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3 years ago

How many seconds did it take (after starting his descent) for the worker to hit the ground? Answer in units of s.

Physics

1 answer:

elena-14-01-66 [18.8K]3 years ago

6 0

Answer:

This question is incomplete

Explanation:

The question is incomplete. However, to determine the time (in seconds) it took a worker to hit the ground from an elevated point. The speed the worker was coming with to the ground and the distance between the elevated point and the ground will have to be considered. Thus the formula to be used here will be

Speed (in meter per second) = distance (in meters) ÷ time (in seconds)

time (in seconds) = distance (in meters) ÷ speed (in meter per seconds)

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Assuming 100% efficient energy conversion, how much water stored behind a 50 centimetre high hydroelectric dam would be required

11Alexandr11 [23.1K]

Complete question is;

Assuming 100% efficient energy conversion how much water stored behind a 50 centimeter high hydroelectric dam would be required to charge the battery with power rating, 12 V, 50 Ampere-minutes

Answer:

Amount of water required to charge the battery = 7.35 m³

Explanation:

The formula for Potential energy of the water at that height = mgh

Where;

m = mass of the water

g = acceleration due to gravity = 9.8 m/s²

H = height of water = 50 cm = 0.5 m

We know that in density, m = ρV

Where;

ρ = density of water = 1000 kg/m³

V = volume of water

So, potential energy is now given as;

Potential energy = ρVgH = 1000 × V × 9.8 × 0.5 = (4900V) J

Now, formula for energy of the battery is given as;

E = qV

We are given;

q = 50 A.min = 50 × 60 = 3,000 C

V = 12 V

Thus;

qV = 3,000 × 12 = 36,000 J

E = 36,000 J

At a 100% conversion rate, the energy of the water totally powers the battery.

Thus;

(4900V) = (36,000)

4900V = 36,000

V = 36,000/4900

V = 7.35 m³

5 0

3 years ago

An underwater diver sees the sun 50° above horizontal. how high is the sun above the horizon to a fisherman in a boat above the

Usimov [2.4K]

Snell's law states that:

n1 Sin∅1 = n2 Sin ∅2

Where, medium 1 with (n1 = 1.33) is water and medium 2 with (n2 = 1) is the air, ∅1 = 90-50 = 40°

Therefore,
Sin ∅2 = n1/n2 *Sin ∅1 = 1.33/1 *Sin 40 = 0.4833=> ∅1 = Sin ^- (0.4833) = 28.9 °

The fisherman the sun at 61.1° (90-∅2) above the horizontal.

3 0

3 years ago

A policeman in a stationary car measures the speed of approaching cars by means of an ultrasonic device that emits a sound with

Ymorist [56]

Answer:

the frequency of the beats is 8.7687 kHz

Explanation:

Given the data in the question;

The frequency for stationary source and moving observer is;

f' = f( 1 +( v_observer/v_sound))

we know that, speed of sound in dry air = 343 m/s

so we substitute

f' = 41.2 kHz( 1 + (33.0 m/s / 343 m/s) ) = 41.2kHz( 1 + 0.0962) = 41.2kHz(1.0962)

f' = 45.1634 kHz

Now the frequency for stationary observer and moving source with frequency f' will be

f" = f'( 1 / (1 - ( v_observer/v_sound)))

45.1634 kHz( 343 / 343 - 33)

we substitute

f" = 45.1634 kHz( 1 / (1 - (33.0 m/s / 343 m/s)))

f" = 45.1634 kHz( 1 / (1 - 0.0962))

f" = 45.1634 kHz( 1 / 0.9038 )

f" = 45.1634 kHz( 1.1064 )

f" = 49.9687 kHz

Now the beat frequency will be;

f_beat = f' - f

we substitute

f_beat = 49.9687 kHz - 41.2 kHz

f_beat = 8.7687 kHz

Therefore, the frequency of the beats is 8.7687 kHz

7 0

3 years ago

Two spheres are made of wood - the first is a variety of wood whose density is equal to that of water, while the second is of a

ki77a [65]

Answer:

The buoyant force experienced by a body is equal to product of unit weight of liguid in which the the objevt is immersed and the volume of liquid replaced by the object.

In the given scenario, bothe the spheres have equal volume and are fully submerged in water. Therefore, the buoyant force experienced by both the spheres will be equal.

5 0

4 years ago

What are 3 ways acceleration can change?

Karolina [17]

Velocity, direction, or both at the same time.

3 0

3 years ago