The official web site of the Nobel Prize explains that Marie Curie’s chemistry prize was partly for her discovery that the radioactivity of a substance is unaffected when it undergoes a chemical reaction. The discovery implied was that, Radioactivity involves Radioactivity involves only neutrons.
Explanation:
- The official web site of the Nobel Prize explains that Marie Curie’s chemistry prize was partly for her discovery that the radioactivity of a substance is unaffected when it undergoes a chemical reaction. The discovery implied was that, Radioactivity involves only neutrons.
- Marie Curie studied about the radiation of all compounds containing the known radioactive elements, including uranium and thorium, which she later discovered that they were radioactive.
- she discovered the following results,
- the exact measurement of the strength of the radiation from uranium;
- the intensity of the radiation was found to be proportional to the amount of uranium or thorium in the compound .
- the ability to emit radiation is not dependent on the arrangement of the atoms in a molecule;
- it must be linked to the interior of the atom itself which is a revolutionary discovery.
Answer:
B)The motion of water in an ocean current
Explanation:
With respect to measurements, a vector has both a magnitude and a direction. The first three examples (maximum height of a hill, air temperature, and rain accumulation) are magnitudes only. The fourth example (motion of water in an ocean current) is a vector, because it has a magnitude (speed) and a direction (with the current).
Answer:
Explanation:
Given that,
Force applied to pedal F = 50N
Angular velocity ω = 10rev/s
We know that, 1rev = 2πrad
Then, ω = 10rev/s = 10×2π rad/s
ω = 20π rad/s
Length of pedal r = 30cm = 0.3m
Power?
Power is given as
P = τ×ω
We need to find the torque τ
τ = r × F
Since r is perpendicular to F
Then, τ = 0.3 × 50
τ = 15 Nm
Then,
P = τ×ω
P = 15 × 20π
P = 942.48 Watts
power delivered to the bicycle by the athlete is 942.48 W
