<u>Answer:</u> The remaining sample of X is 6.9 grams.
<u>Explanation:</u>
All the radioactive reactions follow first order kinetics.
The equation used to calculate rate constant from given half life for first order kinetics:
We are given:
Putting values in above equation, we get:
The equation used to calculate time period follows:
where,
= initial mass of sample X = 78 g
N = remaining mass of sample X = ? g
t = time = 16.5 min
k = rate constant = 
Putting values in above equation, we get:
Hence, the remaining amount of sample X is 6.9 g
Answer:
14.47 m/s
Explanation:
The momentum must be preserved before and after the collision:
The total momentum before the collision
where 
are the masses of the car moving south and north, respectively, before the collision. 
is the velocity of the car moving South. We take the velocity to the North as the positive direction
The total momentum after the collision
where V = 5.22m/s is the velocity of both cars after the collision
We can equalize the 2 equations and plug in the numbers:
Nuclear fusion and gravitational contraction
<span>constituent of star is hydrogen(including isotope) or helium. nuclear fission is almost impossible. D(deuterium; isotope of hydrogen) and T(tritium; also isotope of hydrogen) reacts and helium is formed. During this reaction, severe energy is generated. Heavier elements are formed and pulls each other. Gathered elements forms core of star. Gravity of the core prevents the gas to run away.</span>
Answer:
(i) Momentum of the system is constant
(ii) Total kinetic energy of the system is not constant.
Explanation:
In perfectly inelastic collision, the total momentum of the system is constant while the the total kinetic energy of the system is not constant. The total; kinetic energy is not constant because some of the energy is lost in the process of collision. In this case, two bodies sticks together and both will move with a constant velocity. Also, the coefficient of restitution is equal to 0.
