2.5 kg because you cant change the weight of the rock
Explanation:
This should be of help:
An atom is made up of three subatomic particles:
- Protons are the positively charged particles.
- Electrons are the negatively charged particles.
- Neutrons do not carry any charges.
A neutral atom is an atom that has not lost or gained any amount of electrons.
In a neutral atom;
the number of protons and electrons are the same
Usually atoms are designated this way:
ᵃₙX
where X is the symbol of the atom
a is the mass number of the atom
n is the atomic number of the atom
The mass number = number of protons + number of neutrons
Atomic number = number of protons
Note; atomic number is the same as the number protons and the number of electrons in a neutral atom.
Use this guide to solve the problem
Learn more:
Atomic number brainly.com/question/5425825
#learnwithBrainly
Answer:
the velocity of the bullet-wood system after the collision is 2.48 m/s
Explanation:
Given;
mass of the bullet, m₀ = 20 g = 0.02 kg
velocity of the bullet, v₀ = 250 m/s
mass of the wood, m₁ = 2 kg
velocity of the wood, v₁ = 0
Let the velocity of the bullet-wood system after collision = v
Apply the principle of conservation of linear momentum to calculate the final velocity of the system;
Initial momentum = final momentum
m₀v₀ + m₁v₁ = v(m₀ + m₁)
0.02 x 250 + 2 x 0 = v(2 + 0.02)
5 + 0 = v(2.02)
5 = 2.02v
v = 5/2.02
v = 2.48 m/s
Therefore, the velocity of the bullet-wood system after the collision is 2.48 m/s
20.4 years is 20.4/10.2 = 2 half-life cycles, which means a quarter of the starting mass or 15.2 g will remain after this time.
