Physics Exam Review: Gravitation, Motion, Fluids, and Thermodynamics

Comprehensive practice flashcards covering gravitation, satellite orbits, fluid mechanics, buoyancy, atmospheric pressure, and thermal physics concepts.

What must occur for significant tidal effects from the Moon to be felt on a human body?

Parts of the body would have to be appreciably closer to the Moon than other parts.

How do tidal forces arise?

From unequal forces acting on different parts of a body.

At a point halfway from the surface to the center of a planet with a thin uniform crust that is empty inside, what is an explorer's weight?

Zero.

When the distance between two planets decreases by half, what happens to the gravitational force between them?

The force quadruples.

What change in Earth's acceleration around the Sun occurs if the Sun suddenly collapses into a black hole?

It would stay the same.

If Earth shrinks to a smaller diameter while keeping its mass constant, what happens to your weight on the surface?

Your weight would increase.

If Mo weighs $400\text{ N}$ on Earth's surface, what would he measure his weight to be at the top of a tower extending one Earth radius into space?

About $100\text{ N}$.

A bullet fired horizontally hits the ground in $0.6\text{ s}$. If it were fired with twice the velocity, how long would it take to hit the ground?

$0.6\text{ s}$.

Between the Moon and the Sun, which pulls on Earth's oceans with a greater force?

The Sun.

What is the weight of an occupant inside an elevator that is in free fall?

Zero.

A gravitational force of $360\text{ N}$ acts on an asteroid. What is the force when it is three times farther away?

$40\text{ N}$.

How can a clever merchant profit by buying and selling gold by weight at different elevations at the same selling price?

Buy at a high elevation and sell at a low elevation.

From a $20\text{ m}$ tall tower, a bullet is fired horizontally at $300\text{ m/s}$ over flat ground with no air resistance. How far downrange does it travel?

$600\text{ m}$.

What is the orbital shape of a satellite whose radial velocity is zero?

Circular.

Why does the Moon not crash into Earth?

The Moon has a sufficient tangential speed.

At what point in an elliptical orbit is the angular momentum of a satellite greatest?

It is the same at apogee and perigee.

A rock tossed at $15^\circ$ above the horizon travels the same downrange distance as one tossed at what angle?

$75^\circ$.

At what point in an elliptical orbit is the acceleration of a satellite greatest?

At perigee.

Under what condition does the gravitational force do work on an orbiting satellite?

When the satellite is in an elliptical orbit.

A rock is tossed straight out horizontally from a roof. How far downward has it fallen after $1\text{ s}$?

$5\text{ m}$.

What is the ground speed of a model airplane flying at $10\text{ km/h}$ in a $10\text{ km/h}$ crosswind?

$14.1\text{ km/h}$.

A beaver swims eastward at $1\text{ m/s}$ across a $100\text{ m}$ river flowing southward at $1\text{ m/s}$. How far has it traveled relative to Earth upon reaching the east bank?

$141\text{ m}$.

What happens to the density of an object if its volume is doubled while its mass stays constant?

The density becomes half.

Three brim-filled pools have icebergs: Pool A with air bubbles, Pool B with unfrozen water, Pool C with steel ball bearings. What happens to the water levels when the ice melts?

The water level in C will decrease while the other two water levels will remain the same.

A wooden block floats in water while an equal-sized iron block sits at the bottom. Which experiences the greater buoyant force?

The block of iron.

What is the buoyant force acting on an $8\text{-ton}$ ship floating in the ocean?

$8\text{ tons}$.

A stone weighs $6\text{ N}$ in air and $2\text{ N}$ submerged in water. What is the buoyant force on the stone?

$4\text{ N}$.

A floating raft is loaded with marbles in a swimming pool. If the marbles are thrown overboard, what happens to the pool level?

The pool level will fall.

Why does the buoyant force on a submerged object always act upward?

Upward pressure against the bottom is greater than downward pressure against the top.

To minimize weakening a horizontal I-beam when drilling a hole, where should the hole be placed?

Drilling into the web.

What happens to a helium balloon floating inside a car with closed windows when the car turns left?

The balloon moves to the left.

What is the buoyant force acting on a $2\text{-ton}$ blimp hovering in the air?

$2\text{ tons}$.

If a water barometer stands at $10.3\text{ m}$, how high would an alcohol barometer stand at the same atmospheric pressure?

More than $10.3\text{ m}$.

What happens to the internal pressure within a fluid as its speed increases?

There is less internal pressure.

Why does an umbrella tend to move upward on a windy day?

Air pressure is reduced over the curved top surface.

What is the mass of air in a $1\text{ cm}^2$ column extending from sea level to outer space?

About $1\text{ kg}$.

How deep must an inverted glass filled with air be submerged in water to compress the air volume to one-half?

$10.3\text{ m}$.

Why does an old-style pendulum clock swing slower on a hot day?

The pendulum has stretched and swings less frequently.

Why is the density of ice less than the density of liquid water?

Because ice is made of open-structured, hexagonal crystals.

What happens to the volume of liquid water when warmed from $0^\circ\text{C}$ to $4^\circ\text{C}$?

The volume decreases.

What happens to the volume of ice as it is cooled from $0^\circ\text{C}$ to $-5^\circ\text{C}$?

The volume decreases.

To what temperature must all the water in a lake drop before freezing can occur at the surface?

$4^\circ\text{C}$.

What is the resulting temperature when two liters of $50^\circ\text{C}$ water are mixed with two liters of $10^\circ\text{C}$ water?

At or about $30^\circ\text{C}$.

Aluminum has more than double the specific heat of copper. When equal masses are heated over a flame, which warms up faster?

Copper heats up faster.