physics chapter 10

What is the ratio of escape speed from Earth to circular orbital speed? Ignore air resistance.

1.41

Predict how the vertical component of the velocity will change with time after the projectile is fired.

It first decreases to zero and then increases in the opposite direction

When Dr. Hewitt releases the two objects, how can we tell whether one of the objects hits the ground first or whether they both hit at the same time?

We are able to hear the two balls fall

A ball is thrown horizontally from a cliff at a speed of 10 m/s . You predict that its speed 1 s later will be slightly greater than 14 m/s . Your friend says it will be 10 m/s. Who is correct?

YOU

A giant rotating wheel in space provides artificial gravity for its occupants, as discussed in Chapter 8 in the textbook. Instead of a full wheel, discuss the idea of a pair of capsules joined by a tether line and rotating about each other. Can such an arrangement provide artificial gravity for the occupants?

Yes, but because g must be equal the masses would be close

Escape speed from Earth is any speed equal to or greater than __________.

11.2 km/s

Rank their orbital speed from greatest to least. A. small B. medium C. large

A B C

rank their vertical components of velocity A. 10 m/s & 37 ° B. 20 m/s & 53 ° C. 10 m/s & 45 ° D. 10 m/s & 30 °

B C A D

Rank their time to orbit Earth speed from greatest to least. A. small B. medium C. large

C A B

Can a satellite coast in a stable orbit in a plane that doesn't intersect the Earth's center? Defend your answer.

No because the earth's center is a focus of an elliptical path, so an earth satellite orbits at the center.

For an Earth satellite in an elliptical orbit, list all the values that do change

Speed, gravitational force, and distance from Earth

Which ball (if either) has the greatest speed at the moment of impact?

The ball thrown horizontally

Rank the planets from left to right based on their ORBITAL PERIODS, from longest to shortest. If you think that two (or more) of the diagrams should be ranked as equal. A. 2 earth masses, 1 AU B. 1 earth mass, 1 AU C. 1 earth mass, 2 AU D. 3 earth masses, 2 AU

A=B C=D

rank their horizontal components of velocity A. 10 m/s & 37 ° B. 20 m/s & 53 ° C. 10 m/s & 45 ° D. 10 m/s & 30 °

B D A C

Why do the two objects hit the table at the relative times that they do?

Gravity pulls the same amount on both, and they both drop the same distance.

At what part of an elliptical orbit does an Earth satellite have the greatest speed? The lowest speed?

Greatest nearest Earth; lowest furthest from Earth

In order to appear motionless to an observer at a fixed location on Earth's surface, the satellite must rotate around Earth at the same rate as Earth rotates around its own axis and both the location and satellite must be in the same line between Earth's center and the satellite.

This can only occur above Earth's equator. Above any other location, the "ring" of satellite motion and the "ring" of motion of the location on Earth's surface would not be in the same plane.

Consider the video you just watched. Suppose we replace the original launcher with one that fires the ball upward at twice the speed. We make no other changes. How far behind the cart will the ball land, compared to the distance in the original experiment?

four times as far

rank the planets from left to right based on their average orbital SPEED, from fastest to slowest. A. biggest circle B. bigger oval C. medium circle D. smaller oval E. smallest circle

E D C B A

Rank the positions based on the area that would be swept out by a line drawn between the Sun and the asteroid during the one-week period, from largest to smallest.

THEY ARE ALL EQUAL

Rank the segments of the comet's orbit from left to right based on the LENGTH OF TIME it takes the comet to move from Point 1 to Point 2, from longest to shortest

THEY ARE EQUAL

Rank total energy (KE + PE) from greatest to least. A. below sun B. side of sun C. diagonal right of sun D. above sun

THEY ARE EQUAL

rank their accelerations when they reach the top of their paths. A. 10 m/s & 37 ° B. 20 m/s & 53 ° C. 10 m/s & 45 ° D. 10 m/s & 30 °

THEY ARE EQUAL

How can a projectile "fall around the Earth"?

-The projectile falls 5 m for every 8 km and so does Earth. -A projectile can "fall around Earth" if the distance it falls matches the curvature of Earth. -In a circular orbit around a spherical planet, the force and the fall are always toward the center.

You're in an airplane that flies horizontally with speed 1200 km/h (320 m/s ) when an engine falls off. Neglecting air resistance, assume it takes 35 s for the engine to hit the ground.Find the height of airplane.

6.0 km

You're in an airplane that flies horizontally with speed 1200 km/h (320 m/s ) when an engine falls off. Neglecting air resistance, assume it takes 35 s for the engine to hit the ground.If the airplane somehow continues to fly as if nothing had happened, what is the distance between the engine and the airplane at the moment the engine hits the ground?

6.0 km

Rank KE from greatest to least. A. below sun B. side of sun C. diagonal right of sun D. above sun

A B C D

Rank acceleration from greatest to least. A. below sun B. side of sun C. diagonal right of sun D. above sun

A B C D

Rank gravitational force from greatest to least. A. below sun B. side of sun C. diagonal right of sun D. above sun

A B C D

Rank momentum from greatest to least. A. below sun B. side of sun C. diagonal right of sun D. above sun

A B C D

Rank speed from greatest to least. A. below sun B. side of sun C. diagonal right of sun D. above sun

A B C D

This time, rank the positions (A-D) from left to right based on SPEED the asteroid is moving at each position, from fastest to slowest.

A B C D

When Dr. Hewitt releases the two projectiles, which one hits the ground first?

Both balls hit the ground at the same time.

Rank PE from greatest to least. A. below sun B. side of sun C. diagonal right of sun D. above sun

D C B A

You're in an airplane that flies horizontally with speed 1200 km/h (320 m/s ) when an engine falls off. Neglecting air resistance, assume it takes 35 s for the engine to hit the ground.Find the horizontal distance that the aircraft engine falls.

11 km

Predict how the horizontal component of the velocity will change with time after the projectile is fired.

It stays constant

For an Earth satellite in circular orbit, list all the values that do not change.

Only speed, gravitational force, and distance from Earth

A rocket coasts in an elliptical orbit around Earth. To attain the greatest amount of KE for escape using a given amount of fuel, should it fire its engines to accelerate forward when it is at the apogee or at the perigee? (Hint: Let the formula Fd=ΔKE be your guide to thinking. Suppose the thrust F is brief and of the same duration in either case. Then consider the distance d the rocket would travel during this brief burst at the apogee and at the perigee.)

at the perigee

Why doesn't the force of gravity change the speed of a satellite in circular orbit?

The force is at a right angle to the velocity.

Why is kinetic energy a constant for a satellite in a circular orbit but not for a satellite in an elliptical orbit?

The force of gravity is perpendicular to the motion in a circular orbit but not in an elliptical orbit.

A projectile falls beneath the straight-line path it would follow if there were no gravity. How many meters does it fall below this line if it has been traveling for 1 s? For 2 s?

5 m, 20 m

rank the positions from left to right based on the DISTANCE the asteroid will travel during a one-week period when passing through each location, from longest to shortest. A. orbit=below sun B. orbit= side of sun C. orbit= above left of sun D. orbit= directly above sun

A B C D

rank the segments of the comet's orbit based on the SPEED with which the comet moves when traveling from Point 1 to Point 2, from fastest to slowest. A. 2 = above 1= below B. 1& 2 are below sun C. 1&2 are across & above sun D. 1 & 2 are directly across sun

A B C D

rank the segments of the comet's orbit from left to right based on the DISTANCE the comet travels when moving from Point 1 to Point 2, from longest to shortest. A. 2 = above 1= below B. 1& 2 are below sun C. 1&2 are across & above sun D. 1 & 2 are directly across sun

A B C D

Rank the planets from left to right based on their average orbital DISTANCE from the star, from longest to shortest. A. biggest circle B. bigger oval C. medium circle D. smaller oval E. smallest circle

A B C D E

rank the planets from left to right based on the amount of TIME it takes each to complete one orbit, from longest to shortest A. biggest circle B. bigger oval C. medium circle D. smaller oval E. smallest circle

A B C D E