Week 29 Science HW RWW page 246

1. Units of force are the ___________________ and the ________________.

• Newton ; pound

• kilo ; watts

2. An arrow can be used to represent the ______________ and ______________ of a force.

• displacement ; energy

• strength ; direction

3. Three forces that act on an airplane: _______________, lift, and ______________.

• energy ; force

• thrust ; drag

4. The force that pulls all objects together is called ______________.

• power

• gravity

5. The amount of friction depends on two factors: the roughness of the _______________ of the objects and how much force is required to ________________ the two objects together.

• smoothness ; pull

• roughness ; push

6. ________________ is created whenever there is friction.

• force

• heat

7a. According to the law of inertia, an object at rest tends to _______________ ,

• stay in motion

• stay at rest

7b. ...and object in motion tends to ____________________,

• stay at rest

• stay in motion

7c. ...unless acted upon by an ____________________.

• gravity

• unbalanced force.