Answer:
The final kinetic energy of the two-car system is 60,000 J.
Explanation:
Given;
mass of the car, m = 1200 kg
time of motion, t = 8.8 s
final velocity of the car, v = 10 m/s
Apply the principle of conservation of kinetic energy; the initial kinetic energy is equal final kinetic energy.

Therefore, the final kinetic energy of the two-car system is 60,000 J.
Explanation:
When an object moves in a circular path, it will have circular acceleration. Its magnitude of acceleration is given by :

Since, 

T is the time period
R is the radius of the circular path
To increase the centripetal acceleration bu a factor of 1.5 or 3/2, radius of circle must be increase by a factor of 6 and T is increased by a factor of 2 such that,
R'=6R and T'=2T
So,




Hence, this is the required solution.
Answer:
E = 15.7 KJ/mol
Explanation:
The number of vacancies in a metal is given by
n = n₀
They tell us that
n = 5 no
We replace
5 n₀ = n₀ e^{-E/KT}
-E / KT = ln 5
E = KT ln 5
E = 1,381 10⁻²³ 1170 ln 5
E = 2.6 10⁻²⁰ J
To take (J / mol) we multiply between Avogadro's number
E = 2.6 10⁻²⁰ 6.022 10²³
E = 1.57 10⁴ J / mol
E = 15.7 KJ/mol
The atomic number Z of an element is the number of protons it contains (and in an atom it is equal to the number of electrons). The mass number M is close to the mass of one mol of the substance but it is defined as the number of protons and neutrons in the nucleus of the atom; there, the main mass of the atom is contained. Hence, N=M-Z=74-36=38(since M counts both protons and neutrons while Z only protons). Thus, it has 38 neutrons.