Physics review

) Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them A) increases. B) decreases. C) increases, then decreases. D) decreases, then increases. E) remains constant.

A

A hunter on level ground fires a bullet at an angle of 10 degrees above the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first? A) the dropped one B) the fired one C) Both hit at the same time

A

A lunar month is about 28 days. If the moon were closer to the Earth than it is now, the lunar month would be A) less than 28 days. B) more than 28 days. C) unchanged at 28 days.

A

A lunar month is about 28 days. If the moon were farther from the Earth than it is now, the lunar month would be A) more than 28 days. B) less than 28 days. C) about 28 days. D) difficult to predict without much more information.

A

A projectile is fired into the air at an angle of 50 degrees with the ground and lands on a target that is at the same level at which the projectile started. It will also land on the target if it is fired at an angle of A) 40 degrees. B) 45 degrees. C) 55 degrees. D) 60 degrees. E) none of these

A

A rocket coasts in an elliptical orbit about the Earth. To attain escape velocity using the least amount of fuel in a brief firing time, should it fire off at the apogee, or at the perigee? (Hint: Let "Fd = change in KE" guide your thinking.) A) perigee, where it is closest and fastest B) apogee, where it is farthest and slowest C) same either location

A

A stone is thrown horizontally from the top of a cliff. One second after it has left your hand, its vertical distance below the top of the cliff is A) 5 m. B) 10 m. C) 15 m.

A

A vertically oriented rocket that is somehow able to maintain a continuous upward velocity of 8 km/s will A) escape from the Earth. B) be unable to escape the Earth. C) eventually maintain a fixed orbit around the sun.

A

An Earth satellite is in an elliptical orbit. The satellite travels fastest when it is A) nearest the Earth. B) farthest from the Earth. C) It travels at constant speed everywhere in orbit

A

An Earth satellite is simply a projectile A) freely falling around the Earth. B) floating motionless in space near the Earth. C) approaching the Earth from outer space.

A

An asteroid exerts a 360-N gravitational force on a nearby spacecraft. This force is directed A) toward the asteroid. B) away from the asteroid. C) toward the sun.

A

Compared to the period of satellites in orbit close to the Earth, the period of satellites in orbit far from the Earth is A) longer. B) shorter. C) the same. D) not enough information

A

Consider a moon that orbits one of our most distant planets in an elliptical path. The distance that the moon covers each day is A) greatest when the moon is closest to the planet. B) greatest when the moon is furthest from the planet. C) the same regardless of its distance from the sun. D) the same regardless of its distance from the planet

A

During an eclipse of the sun the high ocean tides on Earth are A) extra high. B) extra low. C) not particularly different.

A

If the mass of the Earth somehow increased with no change in radius, your weight would A) increase also. B) decrease. C) stay the same.

A

If the radius of the Earth somehow decreased with no change in mass, your weight would A) increase. B) not change. C) decrease.

A

Minimal orbital speed about the Earth is about 8 km/s. Minimal orbital speed about the moon would be A) less than 8 km/s. B) more than 8 km/s. C) about 8 km/s.

A

The direction of a gravitational field is A) in the same direction as the gravitational attraction. B) away from the center of gravity of an object. C) opposite to the direction of gravitational attraction.

A

The speeds of the planets about the sun depend on A) their distances from the sun. B) the masses of the planets. C) their periods of rotation. D) None of the above are correct.

A

The tangential velocity of an Earth satellite is its velocity A) parallel to the surface of the Earth. B) perpendicular to the surface of the Earth. C) attributed to satellites moving in any direction.

A

Throw an object upward at a 45 degree angle. With no gravity it will follow a straight-line path. But because of gravity, at the end of 1 second, it is A) about 5 m below the straight line. B) about 10 m below the straight line. C) about 15 m below the straight line.

A

Two projectiles are fired from ground level at equal speeds but different angles. One is fired at an angle of 30 degrees and the other at 60 degrees. The projectile to hit the ground first will be the one fired at (neglect air resistance) A) 30 degrees. B) 60 degrees. C) Both hit at the same time.

A

Which is most responsible for the ocean tides? A) the moon B) the sun C) Both contribute equally.

A

A hollow spherical planet is inhabited by people who live inside it, where the gravitational field is zero. When a very massive space ship lands on the planet's surface, inhabitants find that the gravitational field inside the planet is A) still zero. B) non-zero, directed toward the spaceship. C) non-zero, directed away from the spaceship.

B

A hunter on level ground fires a bullet at an angle of 2 degrees below the horizontal while simultaneously dropping another bullet from the level of the rifle. Which bullet will hit the ground first? A) the dropped one B) the fired one C) Both hit at the same time.

B

A projectile is fired horizontally in a region of no air resistance. The projectile maintains its horizontal component of velocity because A) it is not acted on by any forces. B) it is not acted on by any horizontal forces. C) it has no vertical component of velocity to begin with. D) the net force acting on it is zero. E) none of these

B

A projectile is launched vertically upward at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is A) less than 50 m/s. B) 50 m/s. C) more than 50 m/s.

B

A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its horizontal component of velocity A) increases. B) remains unchanged. C) decreases

B

A weight watcher who normally weighs 400 N stands on top of a very tall ladder so she is one Earth radius above the Earth's surface (Thus the distance doubles) . How much would she weigh there? A) 0 B) 100 N C) 200 N D) 400 N E) none of these

B

Acceleration is greater for a satellite when it is at the A) apogee. B) perigee. C) zenith. D) same acceleration at all of the above places.

B

According to Newton, the greater the masses of interacting objects, the A) less the gravitational force between them. B) greater the gravitational force between them. C) greater the force between them by the square of the masses.

B

An asteroid exerts a 360-N gravitational force on a nearby spacecraft. If the spacecraft moves to a position three times as far from the center of the asteroid, the force will be A) zero. B) 40 N. C) 120 N. D) 360 N. E) 1080 N

B

An object is dropped and freely falls to the ground with an acceleration of 1 g. If it is thrown upward at an angle instead, its acceleration will be A) 0 g. B) 1 g downward. C) 1 g upward. D) larger than 1 g. E) none of these

B

From Earth, one satellite appears to overtake another. The faster satellite is A) higher. B) lower. C) smaller. D) can't say

B

If the Earth's mass decreased to one-half its original mass with no change in radius, then your weight would A) decrease to one quarter your original weight. B) decrease to one half your original weight. C) stay the same. D) none of these

B

If the moon were covered with water, tidal effects caused by the Earth would find the moon with A) 1 tidal bulge. B) 2 tidal bulges. C) 3 tidal bulges. D) 4 tidal bulges. E) no tidal bulges.

B

If you drop a stone into a hole drilled all the way to the other side of the Earth (neglect the molten core), the stone will A) come to an abrupt stop at the center of the Earth. B) speed up until it gets to the center of the Earth. C) speed up until it reaches the other side of the Earth. D) slow down until it reaches the center.

B

Inside a freely falling runaway elevator, your A) acceleration is zero. B) apparent weight is zero. C) gravitational interaction with the Earth is zero. D) all of these E) none of these

B

Newton discovered A) gravity. B) that gravity is universal. C) neither

B

Roll a bowling ball off the edge of a table. As it falls, its horizontal component of velocity A) decreases. B) remains constant. C) increases.

B

The force of gravity does work on a satellite when it is in A) circular orbit. B) elliptical orbit. C) both of these D) neither of these

B

The main reason ocean tides exist is that the pull of the moon A) and sun are in conjunction at high tides and in opposition at low tides. B) is greater on oceans closer to the moon and less on oceans farther from the moon. C) is greater on the Earth because the moon is closer to Earth. D) and the sun on the oceans are in opposite directions. E) none of these

B

Which pulls on the oceans of the Earth with the greater force? A) the moon B) the sun C) Both pull the same

B

) If the sun collapsed to a black hole, the Earth's gravitational attraction to it would be A) more. B) less. C) the same

C

A ball player wishes to determine pitching speed by throwing a ball horizontally from an elevation of 5 m above the ground. The player sees the ball land 20 m down range. What is the player's pitching speed? A) about 5 m/s B) about 10 m/s C) about 20 m/s D) about 25 m/s E) none of these

C

A black hole is A) an empty region of space with a huge gravitational field. B) a small region that contains the mass of many galaxies. C) simply the remains of a giant star that has undergone gravitational collapse.

C

A bullet fired horizontally over level ground hits the ground in 0.5 second. If it had been fired with twice the speed in the same direction, it would have hit the ground in A) less than 0.5 s. B) more than 0.5 s. C) 0.5 s.

C

A gun with a muzzle velocity of 100 m/s is fired horizontally from a tower. Neglecting air resistance, how far downrange will the bullet be 1 second later? A) 50 m B) 98 C) 100 D) 490 E) none of these

C

A projectile is fired vertically from the surface of the Earth at 5 km/s. The projectile will A) go into circular about the Earth. B) go into an elliptical orbit about the Earth. C) rise and fall back to the Earth's surface. D) none of these

C

A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its vertical component of velocity A) increases. B) remains unchanged. C) decreases.

C

A satellite near the Earth makes a full circle in about an hour and a half. How long would a satellite located as far away as the moon take to orbit the Earth? A) the same hour and a half B) less than an hour and a half C) about 28 days D) More information about the satellite is needed. E) none of these

C

A very massive object A and a less massive object B move toward each other under the influence of gravitation. Which force, if either, is greater? A) the force on A B) the force on B C) Both forces are the same

C

According to Newton, doubling the distance between two interacting objects A) divides by 2 the gravitational force between them. B) multiplies by 2 the gravitational force between them. C) divides by 4 the gravitational force between them. D) multiplies by 4 the gravitational force between them.

C

An airplane that flies at 100 km/h in a 100 km/h hurricane crosswind has a ground speed of A) 0 km/h. B) 100 km/h. C) 141 km/h. D) 200 km/h.

C

An airplane travels at 141 km/h toward the northeast. What is its component of velocity due north? A) 41 km/h B) 100 km/h C) 110 km/h D) 141 km/h

C

If the sun somehow became twice as massive, your weight as normally measured here on Earth would A) double. B) quadruple. C) not change.

C

If the sun were twice as massive A) its pull on the Earth would double. B) the pull of the Earth on the sun would double. C) both of these D) neither of these

C

If your mass, the mass of the Earth, and the mass of everything in the solar system were twice as much as it is now, yet everything stayed the same size, your weight on Earth would A) be the same. B) double. C) quadruple. D) be eight times as much as now. E) none of these

C

It takes Pluto a longer time to orbit the sun than the Earth does because Pluto A) has much further to go. B) goes much slower. C) Choices A and B are both correct. D) none of the above

C

No force due to Earth's gravity is acting on the astronauts inside the orbiting space shuttle. This statement is A) always true while in orbit. B) sometimes true while in orbit. C) always false.

C

The fastest moving planet in a solar system is A) the smallest planet. B) the most massive planet. C) the planet nearest the sun. D) the planet farthest from the sun. E) any planet, for they all move at the same speed.

C

The period of a satellite, the time it takes for a complete revolution, depends on the satellite's A) mass. B) weight. C) radial distance. D) all of these E) none of these

C

The planet Jupiter is about 300 times as massive as Earth, yet on its surface you would weigh only about 3 times as much. This is because A) your mass is 100 times less on Jupiter. B) Jupiter is significantly farther from the sun. C) Jupiter's radius is 10 times the Earth's radius. D) you are 100 times more weightless there. E) none of these

C

Tidal forces in general are the result of A) two or more sources of gravitation. B) a combination of any kind of forces acting on a body. C) unequal forces acting on different parts of a body. D) the inverse-square law. E) unequal fluid flow.

C

What is the force of gravity on a 500-newton woman standing on the Earth's surface? A) 50 N B) 250 N C) 500 N D) 5000 N E) none of these

C

When a star collapses to form a black hole, its mass A) increases. B) decreases. C) remains the same

C

When you step on a weighing scale at noon, the Earth pulls you down and the overhead sun pulls you upward. The reason the sun's pull doesn't decrease your weight at noon is because A) the sun's pull on you is negligibly small. B) the weighing scale is calibrated only in Earth weight. C) you, the scale, and the Earth are in free fall (in orbit) around the sun. D) the sun's pull is cancelled by the gravitation of other celestial bodies. E) of tidal effects in the "solid" Earth.

C

A projectile is launched at ground level an angle of 15 degrees above the horizontal and lands down range. What other projection angle for the same speed would produce the same down-range distance? A) 30 degrees B) 45 degrees C) 50 degrees D) 75 degrees E) 90 degrees

D

Our moon travels the fastest as it orbits the Earth when it is A) performing an eclipse. B) rotating. C) revolving. D) closest. E) All of the above choices are true.

D

The factor most directly responsible for making a black hole invisible is its A) size. B) mass. C) color. D) surface escape velocity. E) none of these

D

When the distance between two stars decreases by half, the force between them A) decreases by one-quarter. B) decreases by one-half. C) increases to twice as much. D) increases to four times as much. E) stays the same.

D

) There would be only one ocean tide per 24-hour day if the A) Earth and moon were equally massive. B) moon were more massive than the Earth. C) sun's influence on the tides were negligible. D) moon's mass were small - only a few kilograms. E) none of these

E

A bullet is fired horizontally with an initial velocity of 300 m/s from a tower 20 m high. If air resistance is negligible, the horizontal distance the bullet travels before hitting the ground is about A) 200 m. B) 300 m. C) 400 m. D) 500 m. E) 600 m.

E

All places on the Earth would have high tides at the same instant if the A) moon did not revolve. B) moon did not rotate. C) sun did not revolve. D) sun did not rotate. E) None of the above choices are correct.

E

Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them is also doubled, then the force between them is A) one quarter. B) half as much. C) twice as much. D) four times as much. E) none of these

E

Half way to the center of a completely hollow planet with a thin uniform shell, your weight would be A) one-quarter of your weight on the surface. B) one-half of your weight on the surface. C) three-quarters of your weight on the surface. D) the same as at the surface. E) zero.

E