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Sphinxa [80]
3 years ago
12

the half life of a certain substance is 25 years. How long will it take for a sample of this substance to decay to 90% of its or

iginal amount ...?
Physics
1 answer:
Sveta_85 [38]3 years ago
3 0
10% =  1/2 ^n
*where n is number of half lives to reach 10%

n = ln10/ln2

and multiply by 25 gives 83.05 years to 2dp

Hope this helps
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Newtons First Law of Motion:
An object at rest stays at rest and an object in motion<span> stays in </span>motion <span>with the same speed and in the same direction unless acted upon by an unbalanced force.</span>

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An extreme skier, starting from rest, coasts down a mountain slope that makes an angle of 25.0 with the horizontal. The coeffici
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Answer:

V = 10.88 m/s

Explanation:

V_i =initial velocity = 0m/s

a= acceleration= gsinθ-\mu_kcosθ

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using the equation

v^2_f=v^2_i-2as

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v_f= 7.04 m/s

let the speed just before she lands be "V"

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6 0
3 years ago
What is the equation describing the motion of a mass on the end of a spring which is stretched 8.8 cm from equilibrium and then
Sedbober [7]

Answer:

x=(0.088m)\cos(\sqrt{\frac{k}{m} }  t)

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x=(0.088m)\cos(\sqrt{\frac{k}{m} }  t)

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3 years ago
As an object rolls downhill, some of the energy is
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<em>Distance from the pivot =  3 cm </em>

8 0
3 years ago
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