AST101: The Sun and its Neighbours - Class 7: Tides

These flashcards cover key concepts from AST101: The Sun and its Neighbours, focusing on Newton's laws, gravitational forces, and tidal phenomena.

What does Newton's first law state?

An object in motion remains in motion unless acted upon by an outside force.

What is the formula for Newton’s second law?

A = F/m; where acceleration is proportional to force and inversely proportional to mass.

What is described by Newton’s third law?

For every force, there is always an equal and opposite reaction force.

What does Newton’s Universal Law of Gravitation express?

F = G (M1M2)/d^2; the force between two objects is proportional to their masses and inversely proportional to the square of the distance between them.

How does doubling the distance between two objects affect the gravitational force?

It reduces the force by a factor of 4.

When is the gravitational force between a comet and the Sun greatest?

When the comet is closest to the sun.

What happens if a satellite exceeds escape velocity?

It travels into space, moving too fast for gravity.

Why does an astronaut float in space?

Because he is in orbit, traveling at a speed where the force of gravity equals the force required to keep him in a circular path.

What is tidal locking?

When the moon has stopped rotating relative to the earth due to the tidal forces from the Earth.

What are spring tides?

Tides that occur when the Sun, Moon, and Earth are lined up, resulting in the largest tides.

What are neap tides?

Tides that occur when the Sun and Moon are minimally aligned, resulting in the smallest tides.

How many high and low tides occur per day?

Two high tides and two low tides.

What role does the sun play in tidal forces?

The sun causes additional tidal forces that can enhance or cancel the tides caused by the moon.

What is the relationship between gravitational force and mass?

The gravitational force increases with the product of the masses of two objects.

In tidal behavior, what causes the tidal bulge to lag behind the Earth’s rotation?

Friction with the rotating Earth causes the tidal bulge to lag behind.