HW #4 Gravity, Projectiles, and Satellites

Flashcards covering key concepts of gravity, projectiles, and satellites.

What happens to the force of gravity between two bodies when the distance between them is tripled?

The force of gravity decreases to one-ninth of its original value.

Where do you weigh more—at sea level or atop one of the peaks of the Rocky Mountains?

You weigh more at sea level due to being closer to Earth's center, which increases gravitational force.

How does the compression of springs in a bathroom scale change in an elevator moving upward at constant velocity?

The springs are neither more nor less compressed; weight remains unchanged.

How does the compression of springs in a bathroom scale change in an elevator moving downward at constant velocity?

The springs are neither more nor less compressed; weight remains unchanged.

What happens to the horizontal component of a stone thrown upward at an angle along its trajectory?

The horizontal component of its velocity remains constant, neglecting air resistance.

For a projectile launched at 75° angle, what is the other angle at the same speed that lands the projectile just as far away?

The other angle is 15°.

If a satellite were beyond Earth’s gravity, what path would it follow?

It would follow a straight line path in space due to inertia.

Why does the force of gravity change the speed of a satellite in an elliptical orbit?

Gravity varies with distance from the Earth, which causes changes in speed.

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

At the closest point to Earth (perigee).

At what part of an elliptical orbit does an Earth satellite have the least speed?

At the farthest point from Earth (apogee).

What happens to an object close to Earth’s surface if it exceeds a speed of 11.2 km/s?

It escapes Earth's gravitational pull and enters orbit or travels into space.

What two forces act on you while in a moving elevator?

Gravitational force and the normal force from the elevator floor.

When are the forces acting on you in a moving elevator of equal magnitude?

When the elevator moves at constant velocity (either up or down).

When are the forces acting on you in a moving elevator not of equal magnitude?

When the elevator accelerates (either upward or downward).