Gravitational potential energy can be calculated using the formula <span>PE = m × g × h, where g is the gravitational acceleration and is constant hence the energy is dependent directly to mass and the height of the object. Hence more PE is registered when the object is heavier and/or at greater initial height. </span>
Answer: d) the presence of solidified lava flows on the Moon
Explanation:
A geological activity means an occurrence of event such as volcanic eruption, earthquake, sedimentation, erosion etc. The revolution of the Moon around the Earth
, the axial tilt of the Moon or the phases of the Moon are not surface features. hence, these events cannot provide the evidence of geological activity in the past of Moon.
The surface features of moon such as Mares, Craters, mountains, Rays and rills are the proof of some geological activity on the Moon. Mares are the dark patches on the moon's surface formed of solidified lava. Due to negligible atmosphere on the moon, the meteors strike its surface and cause craters to form. Thus, the correct answer is d.
Answer:
diameter = 21.81 ft
Explanation:
The gravitational force equation is:

Where:
- F => Gravitational force or force of attraction between two masses
- M => Mass of asteroid 1
- m => Mass of asteroid 2
- R => Distance between asteroids 1 and 2 (from center of gravity)
We also know that the asteroids are identical so their masses are identical:
Since R is the distance between centers of the two asteroids and their diameters are identical (see attachment), we can conclude that:
We don´t know the mass of the asteroids but we know they are composed of pure iron, so we can relate their masses to their density:
This is going to be helpful because the volume of a sphere is:
And know we can write our original force of gravity equation in terms of the radius of the asteroids:
Now let´s plug in the values we know:
mutual gravitational attraction force
gravitational constant
Solve for r and multiply by 2 because 2r = diameter
Result is d = 21.81 Feet
Answer: D
Rs = 10.0 m/s
The speed of the boat relative to an observer standing on the shore as it crosses the river is 10.0m/s
Explanation:
Since the boat is moving perpendicular to the current of the river, the speed of the boat has two components.
i. 8.0m/s in the direction perpendicular to the current
ii. 6.0m/s in the direction of the current.
So, the resultant speed can be derived by using the equation;
Rs = √(Rx^2 + Ry^2)
Taking
Ry = 8.0m/s
Rx = 6.0m/s
Substituting into the equation, we have;
Rs = √(6.0^2 + 8.0^2)
Rs = √(36+64) = √100
Rs = 10.0 m/s
The speed of the boat relative to an observer standing on the shore as it crosses the river is 10.0m/s