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Rasek [7]
3 years ago
8

Half life of a given sample of radium is 22 years the sample will reduce to 25% of its original value after

Physics
1 answer:
makkiz [27]3 years ago
3 0

Answer:

44 years

Explanation:

Use half life equation:

A = A₀ (½)^(t / T)

where A is the final amount,

A₀ is the initial amount,

t is time,

and T is the half life.

0.25 A₀ = A₀ (½)^(t / 22)

0.25 = (½)^(t / 22)

t / 22 = 2

t = 44

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In normal light conditions, how well do plants grow when there are 10 plants in the
Sati [7]

Answer

when there are ten they don't grow so well but when there is less than 10 they tend to grow

7 0
3 years ago
A car generator turns at 400 rpm (revolutions per minute) when the engine is idling. It has a rectangular coil with 300 turns of
Sav [38]

The field strength needed to produce a 24.0 V peak emf is 0.73T.

To find the answer, we need to know about the expression of emf.

What's the expression of peak emf produced in a rotating rectangular loops?

  • The peak emf produced in a rotating loops= N×B×A×w
  • N= no. of turns of the loop, B= magnetic field, A= area of loop and w= angular frequency
  • So, B = emf/(N×A×w)
<h3>What's the magnetic field applied to the loop, when rectangular coil with 300 turns of dimensions 5.00 cm by 5.22 cm rotates at 400 rpm produce a 24.0 V peak emf?</h3>
  • N= 300, A= 5cm × 5.22cm = 0.05m × 0.0522m = 0.00261 m²
  • Emf= 24V, w= 2π×400 rpm= 2π×(400rps/60) = 42 rad/s
  • Now, B= 24/(300×0.00261×42)

B= 24/(300×0.00261×42) = 0.73T

Thus, we can conclude that the magnetic field is 0.73T.

Learn more about the electromagnetic force here:

brainly.com/question/13745767

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6 0
2 years ago
A 1000 kg car moving a 10 m/s collides with a stationary 2000 kg truck. The two vehicles interlock as a result of the collision.
IgorLugansk [536]

Answer:

v₃ = 3.33 [m/s]

Explanation:

This problem can be easily solved using the principle of linear momentum conservation. Which tells us that momentum is preserved before and after the collision.

In this way, we can propose the following equation in which everything that happens before the collision will be located to the left of the equal sign and on the right the moment after the collision.

(m_{1}*v_{1})+(m_{2}*v_{2})=(m_{1}+m_{2})*v_{3}

where:

m₁ = mass of the car = 1000 [kg]

v₁ = velocity of the car = 10 [m/s]

m₂ = mass of the truck = 2000 [kg]

v₂ = velocity of the truck = 0 (stationary)

v₃ = velocity of the two vehicles after the collision [m/s].

Now replacing:

(1000*10)+(2000*0)=(1000+2000)*v_{3}\\v_{3}=3.33[m/s]

7 0
3 years ago
A ball is thrown straight up from ground level. It passes a 2-m-high window. The bottom of the window is 7.5 m off the ground. T
slamgirl [31]

Answer:

u=14.48m/s

Explanation:

From the question we are told that:

Height of window h=2m

Height of window off the ground h_g=7.5m

Time to fall and drop t=1.3s

 

Generally the Newton's equation motion  is mathematically given by

 s=ut+\frac{1}{2}at^2

Where

h=ut+\frac{1}{2}at^2

2=u1.3-\frac{1}{2}*9.8*1.3^2

2=u1.3-8.281

u=7.91m/s^2  

Generally the Newton's equation motion  is mathematically given by

2as=v^2-u^2

Where

-2gh_g=v^2-u^2

-2*9.8*7.5=(7.91)^2-u^2

-147=62.5681-u^2

u=\sqrt{209.5681}

u=14.48m/s

Therefore the  ball’s initial speed

u=14.48m/s

8 0
3 years ago
Choose all the answers that apply.
spin [16.1K]

Answer:

B and C?

Explanation:

3 0
3 years ago
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