Answer:
It will sink
Explanation:
An object in the water can float only if its density is lower than the density of the water.
In fact, for an object completely immersed in water, there are two forces acting on it:
- Its weight, , downward, where is the density of the object, V its volume and g the gravitational acceleration
- The buoyant force, , upwards, there is the density of the water
We see that when the density of an object is larger than the density of the water, , the weight is greater than the buoyant force, , so the object sinks.
In this case, the rock has a density of 1.73 g/cm3, while water has a density of 1.0 g/cm^3, so the rock will sink.
C involves sound waves not electromagnetic waves (light)
Answer:
Explanation:
The <em>half-life </em>of a radioisotope, in this case carbon-14, is the time that a sample requires to reduce its amount to half, and it is a constant for every radioisotope (it does not change with the amount of sample).
Then, the formula for the remaining amount of a radioisotope is:
Where:
- A is the final amount of the element,
- A₀ is the initial amount of the element,
- A/A₀ is ratio of remaining amount to the original amount, and
- n is the number of half-lives elapsed
The number of half-lives for carbon-14 elapsed for the dinosaur fossil is:
- n = 68 million years / 5730 years ≈ 11,867
Then, A / A₀ = (1/2)ⁿ = (1/2)¹¹⁸⁶⁷ ≈ 0.00000 .
The number is too small, and when you round to five decimal places the result is zero. That is why carbon-14 cannot be used to date dinosaur fossils, given that they are too old.
Answer:
Both balls hit the ground simultaneously
Explanation:
Let´s call b₁ ( the ball dropped ) the equation for a free fall movement is, tacking as the origin of coordinates the level from which it was dropped
V = g*t ( since V₀ initial velocity is 0 )
In the case of projectile movement the equation for Vx and Vy (these speeds are independent)
are:
Vx = V₀x (constant) and Vy = Voy + g*t
Vy = V₀ * sin 0⁰ + g*t Vy = 0 + g*t
As we can see V is the same in both cases then the balls hit the ground simultaneously