<span>c. atoms are always in motion..............</span>
Via half-life equation we have:

Where the initial amount is 50 grams, half-life is 4 minutes, and time elapsed is 12 minutes. By plugging those values in we get:

There is 6.25 grams left of Ra-229 after 12 minutes.
Answer:
Explanation:
Actual weight, Wo = 5 N
Apparent weight, W = 4.5 N
density of water = 1 g/cm^3 = 1000 kg/m^3
density of gold, = 19.32 g/cm^3 = 19.32 x 1000 kg/m^3
Buoyant force = Actual weight - Apparent weight
Volume x density of water x g = 5 - 4.5
V x 1000 x 9.8 = 0.5
V = 5.1 x 10^-6 m^3
Weight of gold = Volume of gold x density of gold x gravity
W' = 5.1 x 10^-6 x 19.32 x 1000 x 9.8 = 0.966 N
As W' is less than W so, it is not pure gold.
First law is Conservation of Energy
Second is that entropy of an isolated system will always increase with time.
Entropy is the change of disorder through time. The best statement which relates to the 2nd law is C. Thermal energy flows from areas of higher to lower temperature
Answer:
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- <u><em>1,500 kg.m/s</em></u>
Explanation:
First, arrange the information in a table:
Object Mass (kg) Velocity (m/s)
A 200 15
B 150 - 10
After the collision, the two objects are stick together, thus you talk aobut one object and one momentum.
According to the law of convervation of momentum, the momentum after the collision is equal to the momentum before the collision.
<u>Momentum before the collision, P₁</u>:


<u>Momentum after the collision</u>:
- As stated, it es equal to the momentum before the collision: 1,500 kg . m/s