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Maurinko [17]
3 years ago
9

How long must you wait (in half-lives) for a radioactive sample to drop to 2.10 % of its original activity?

Physics
1 answer:
MArishka [77]3 years ago
6 0

Answer:

222/88 Ra

Explanation:

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A current of 6.93 A 6.93 A in a long, straight wire produces a magnetic field of 4.15 μT 4.15 μT at a certain distance from the
natka813 [3]

Answer:

0.334 m

Explanation:

The magnetic field due to current in a straight thin wire, B, is given by

B = \dfrac{\mu_0 I}{2\pi R}

where \mu_0 is the permeability of free spave with value 4\pi\times10^{-7} and R is the distance from the wire.

R = \dfrac{\mu_0 I}{2\pi B}

Substituting the values from the question,

R = \dfrac{4\pi\times10^{-7}\times 6.93}{2\pi\times 4.15\times 10^{-6}}

R = \dfrac{2\times10^{-1}\times6.93}{4.15} = 0.334 \text{ m}

7 0
4 years ago
Read 2 more answers
Despite a very strong wind, a tennis player manages to hit a tennis ball with her racquet so that the ball passes over the net a
kobusy [5.1K]

Answer:

The downward force of gravity and the force exerted by the air.

Explanation:

Gravity, in a Newtonian Framework, acts at distance, so, the ball doesn't has to be connected to Earth to feel its gravitational pull (as we know by experience).

The racket only can exert a force in the ball when is touching it, so, once the ball has left the contact with the racket, there is no force by the "hit".

The air is always touching the ball on the atmosphere (even when physicist pretend that is not). So, there is drag from the wind, and a buoyant force  exerted by the air over the ball at every time.

5 0
4 years ago
Across a horizontal distance of 25 feet, a roller coaster has a steep drop. The height of the roller coaster at the bottom of th
allsm [11]

X = total horizontal distance = 25 ft

Y = total vertical distance = 125 ft

x = horizontal distance = 1 ft

y = vertical distance = ?

using the equation

y = (Y/X) (x)

inserting the values

y = (125/25) (1)

y = 5 ft

hence for each horizontal foot, the average height change is 5 ft

or

25 ft horizontal distance traveled = 125 ft vertical distance dropped

dividing both side by 25

25 ft horizontal distance traveled/25 = 125 ft vertical distance dropped/25

1 foot horizontal distance traveled = 25 ft vertical distance dropped

6 0
3 years ago
Read 2 more answers
Flag question
anastassius [24]

Answer:

P = density (p) * g * h

P = 1000  kg/m^3 * 9.8 m/s^2 * 40 m = 392,000 N/m^2

since kg m / s^2 = Newtons

The average pressure is 1/2 (pressure at 0m +  pressure 80 m) for liquid of uniform density

3 0
3 years ago
The density of a mineral is determined by its mass and
My name is Ann [436]

Answer: specific gravity

8 0
4 years ago
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