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egoroff_w [7]
2 years ago
15

The private papers of what scientist had to be decontaminated for two years in the 1990's before being put on file at the Nation

al Library in Paris? 577 points
Physics
1 answer:
SashulF [63]2 years ago
3 0
The answer is Marie Skłodowska Curie (AKA Marie Curie). She <span>lived her life awash in ionizing radiation. She would be carrying bottles of the radium and polonium in the pocket of her coat and put them in her desk drawer. 
So even after a century, her papers are still radioactive. Since the</span><span> most general isotope of radium, which is radium-226, has a half life of 1,601 years.</span>
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The strongest ernergy wave in the EM Spectrum is 'microwave'<br> true<br> false
Ratling [72]
Pretty sure it’s false....................
6 0
2 years ago
What are 5 differences between Spring Tides and Neap Tides?
ad-work [718]

Spring Tides are formed by the constructive interference of bulges created by the moon and sun. Spring Tides occur when the Sun, Moon and the Earth are aligned. Neap Tides are formed by the destructive interference created by the moon and sun. Neap tides occur when the Sun, Moon, and Earth align to make a right angle.
4 0
3 years ago
A motorboat traveling 4 m/s, East encounters a current traveling 3.0 m/s, North. a) What is the resultant velocity of the motorb
Nostrana [21]

Explanation:

It is given that,

Velocity in East, v_1=4\ m/s

Velocity in North, v_2=3\ m/s

(a) The resultant velocity is given by :

v=\sqrt{4^2+3^2}=5\ m/s

(b) The width of the river is, d = 80 m

Let t is the time taken by the boat to travel shore to shore. So,

t=\dfrac{d}{v}

t=\dfrac{80\ m}{5\ m/s}

t = 16 seconds

(c) Let x is the distance covered by the boat to reach the opposite shore. So,

x=v_2\times t

x=3\ m/s\times 16\ s

x = 48 meters

Hence, this is the required solution.

4 0
3 years ago
A child slides down a hill on a toboggan with acceleration of 1.8 m/s2. if she starts from rest, how far has she traveled in:
Stells [14]

A child slides down a hill on a toboggan with acceleration of 1.8 m/s2. if she starts from rest, how far has she traveled in: 2 seconds

Answer:

2.4 m

Explanation:

From the question above,

Applying equation of motion,

s = ut+at²/2....................... Equation 1

Where t = time, u = initial velocity, a = acceleration,  s = distance.

make s the subject of the equation,

Given: a = 1.8 m/s²,  t = 2 seconds, u = 0 m/s (from rest)

Substitute these value into equation 1

s = 0(2)+1.8(2²)/2

s = 1.2(4)/2

s = 2.4 m.

Hence she has traveled 2.4 m

4 0
3 years ago
Two forces F1 and F2 of equal magnitude are applied to a brick of mass 20kg lying on the floor as shown in the figure above. If
jeka57 [31]

Let F_{1}=F_{2}=F.

Normal force equals (using Newton's third law) N=mg+F\sin30^{o}-F\sin37^{o}.

F_{f}\leq \mu N = \mu(mg+F\sin30^{o}-F\sin37^{o}), but F_{f}\leq F(\cos30^o+\cos37^o) for all F_{f} (in order to start moving the break). Therefore F(\cos 30^o+\cos37^o)\geq \mu(mg+F\sin30^{o}-F\sin37^{o}), solving for F: F\geq \frac{\mu mg}{\cos30^o+\cos37^o-\mu\sin30^o+\mu\sin37^o}\approx 46,91\; \textbf{N}

7 0
2 years ago
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