# Physical Science: Motion, Forces, and Energy, Book M

## Section 3: Newton's Third Law

### Self-Check Quiz-Eng.

 1. Newton's third law of motion states that __________. Need a Hint? A) an object will remain at rest or keep moving in a straight line with constant speed unless a force acts on it B) when a force is applied on an object, there is an equal force applied by the object in the opposite direction C) acceleration is calculated by dividing the force exerted on an object by the mass of the object, and that when a force acts on an object, its acceleration is in the same direction as the force D) the force on an object can be found by dividing its mass by its acceleration 2. __________ measures the quantity of matter of an object. Need a Hint? A) Mass B) Weight C) Net force D) Density 3. The two forces of a force pair are called the __________ force and the __________ force. Need a Hint? A) mass, acceleration B) gravitational, accelerator C) increasing, decreasing D) action, reaction 4. Friction always acts __________ the direction of motion of an object. Need a Hint? A) in the same direction as B) perpendicular to C) opposite to D) at a 45° angle to