Chapter 5- Physics: Gravity (Integrated Science)

A projectile is launched at an angle of 15° above the horizontal and lands downrange. What other projection angle for the same speed would produce the same downrange distance 30° 45° 50° 75° 90

75°

8. What prevents satellites such as the space shuttle from falling? A)gravity B) centripetal force C) centrifugal force D) the absence of air drag E) Nothing, they continually fall all around Earth.

Nothing, they continually fall all around Earth

The Earlybird communication satellite hovers over the same point on Earth's equator indefinitely. This is because A) Forces other than Earth's gravity act on it.? B) It pulls as hard on Earth as Earth pulls on it. ? C) it is beyond the main pull of Earth gravity. ? D) It is kept aloft by ground control. E) its orbital period is 24 hours.

its orbital period is 24 hours.

6. Minimal orbit speed about 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.

less than 8 km/s.

7. According to Newton, the greater the distance between masses of interacting objects, the A) less the gravitational force between them. B) more the gravitational force between them.

less the gravitational force between them

4. Consider two planets in space that gravitationally attract each other. If the masses of both planets is 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 the above

none of the above

9. A projectile is fired vertically from the surface of Earth at 10 km/s. The projectile will A) go into circular orbit about Earth. B) go into an elliptical orbit about Earth. C) rise and fall back to Earth's surface. D) none of the above

none of the above

10. Communications and weather satellites always appear at the same place in the sky. This is because these satellites are A) beyond the pull of Earth's gravitational field. B) moving at a speed just short of escape velocity. C) orbiting Earth with a 24-hour period. D) stationary in space. E) none of the above

orbiting Earth with a 24-hour perioD

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

remains unchanged.

5. A hunter aims a rifle at an angle of 10° below the horizontal. The hunter fires a bullet 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 will hit at the same time.

the fired one