4.1 Gravitational Force Near Earth

Question 1

free fall

Answer 1

the motion of a falling object where the only force acting on the object is gravity

Question 2

The force of air resistance acting on an object depends on many factors like…

Answer 2

One factor is the cross-sectional area of the object. -larger cross-sectional areas experience more air
resistance than smaller cross-sectional areas

Factor that affects the force of air resistance is the speed of the object.
-faster-moving objects experience more air
resistance
-air resistance acts opposite to the direction of
motion of the object if there is no wind.

Question 3

terminal speed

Answer 3

the maximum constant speed of a falling object

Question 4

force field

Answer 4

a region of space surrounding an object that can exert a force on other objects that are placed within that region and are able to interact with that force

Question 5

gravitational field strength

Answer 5

the force per unit mass acting on an object when placed in a gravitational field

-vector quantity because it has a direction

-at Earth’s surface, the gravitational field strength is
9.8 N/kg [down].

Question 6

gravitational field strength at a location has the same _____ as the ________ due to gravity at that location.

Answer 6

magnitude; acceleration

Question 7

To determine the gravitational field strength at a particular location, you can …

Answer 7

measure the force of gravity acting on an object using a spring scale or force sensor and divide by the mass of the object

Question 8

Careful measurements of Earth’s gravitational field strength show that its magnitude _____ as an object is moved farther away from Earth’s surface.

If the distance is large enough, Earth’s gravitational field strength becomes very _____.

Answer 8

decreases; weak

Question 9

Since Earth is not a perfect sphere, the magnitude of the gravitational field strength at Earth’s surface, varies according to …

Answer 9

the geographic location of the object

Question 10

the magnitude of the gravitational field strength is slightly ______ at the poles than at the equator.

Answer 10

greater

Question 11

The magnitude of the gravitational field strength gradually increases with ________ as you travel from the equator toward either pole.

Answer 11

latitude

Question 12

the gravitational field strength on Earth’s surface is …

Answer 12

9.8 N/kg [down]

Question 13

mass

Answer 13

quantity of matter in an object

Question 14

-the only way to change the mass of an object is to either …

Answer 14

add or remove matter

Question 15

-the mass of an object does not change due to

Answer 15

location or changes in gravitational field strength.

Question 16

Weight

Answer 16

a measure of the force of gravity acting on an object

Question 17

Since weight and the force of gravity are the same ________, the weight of an object depends on
________ and the _________ of Earth’s gravitational field strength at that location.

Answer 17

quantity; location; magnitude

Question 18

true or false

weight is a vector

Answer 18

true

Question 19

when measuring weight with a force sensor or a spring scale, the object must either be ______________________ while being supported by the scale or sensor.

Answer 19

at rest or moving at a constant velocity

Question 20

On the Moon or a planet other than Earth, your weight is ________ but your mass is the ________.

Answer 20

different; same

Question 21

gravitational field strength

Answer 21

force per unit mass acting on an object placed in a gravitational field

Question 22

The gravitational field strength at Earth’s surface __________ with distance from the surface of
Earth. It is ___________ at the poles and _______ at the equator because Earth is not a perfect sphere.

Answer 22

decreases; greater; less