Answer:
Calcium and barium
Explanation:
Krypton is a noble gas it do not take part in any reaction its physical and chemical property does not resembles to other atoms.
Hydrogen is the reducing gas its physical and chemical property does not resembles to other atoms.
Silicon is a semiconductor its physical and chemical property does not resembles to other atoms.
Calcium and Barium are placed in the same group 2 in the periodic table . Both are alkaline earth metal.
As both element are placed in the same group they have same physical and chemical properties.
Example:
- Electro-negativity of Calcium and barium are approximately same.
- Both have same oxidation states +2, both are strong basic oxide.
- Both are present in nature in solid state.
- Both are s- block element.
Thus, we can say Barium and Calcium have similar properties.
Answer:
Newton's paw of universal gravitation states that a particle attracts every other particle in the universe using a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance in between them
Answer:
a. 2865 km
Explanation:
Eratosthenes observed that the sun's rays formed a vertical angle of 7º 12 ’. Which confirmed that the Earth was not flat, assuming that it had a spherical shape, using the distance between Alexandria and Siena and the measure of the angle of inclination of the solar rays in Alexandria, calculated the circumference of the Earth.
The calculation was made with a simple rule of three:
angle of inclination of the solar rays——————- distance
360º ————- Planet circumference
And since we know that:
Answer: distance = 24 meters
Explanation:
speed = distance / time
distance = speed x time
speed = 160 cm/s = 1.6 m /s [ 100 cm = 1 m, 160 cm = 1.6 m ]
time = 15 s
distance = 1.6 m/s x 15 s = 24 m
