In my opinion the answer is D
Answer: Option (D) 30N
Detailed Solution:
According to Newton's second law:
F = ma --- (A)
Given:
mass = 5kg
acceleration = 6 m/s^2
F = ?
Plug all the value in equation (A)
F = (5)(6)
Ans: F = 30N
A pure substance has a constant composition and cannot be separated into simpler substances by physical means. There are two types of pure substances: elements and compounds. Elements: are pure substances made up of only l type of atom. Atoms of the same element are identical in properties.
Answer: Uranium-235.
Radioactive isotopes are used to determine the age of antique objects, including fossils.
The half-life time of the radioactive elements is what permits the process of dating.
The half-life of C-14 is too short to be useful to date too old objects.
Precambrian time is the most antique era. C-14 hal-life is about 5730 years and Precambrian time is millions or billions of years ago. Given that the hal-life of U-235 is 704 million years it is appropiate to date the fossils from the Precambrian era.
