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

## Section 1: Newton's First Law

### Self-Check Quiz-Eng.

 1. A(n) __________ is a push or a pull. Need a Hint? A) motion B) velocity C) acceleration D) force 2. The __________ is the combination of all the forces acting on an object. Need a Hint? A) direction of motion B) force pair C) inertia D) net force 3. Forces that cancel each other are called __________ forces. Need a Hint? A) neutral B) balanced C) inactivated D) null 4. When balanced forces act on an object, the net force is __________. Need a Hint? A) positive B) zero C) negative D) increased due to friction 5. When unbalanced forces act on an object, __________. Need a Hint? A) the object accelerates B) the net force is zero C) the object speeds up D) friction becomes greater than the net force 6. __________ is a force that resists motion between two surfaces that are in contact. Need a Hint? A) Resistance B) Inertia C) Friction D) Acceleration 7. Newton's first law of motion states that __________. Need a Hint? A) an object will remain at rest or keep moving with a constant velocity unless a force acts on it B) acceleration is calculated by dividing the force exerted on an object by the mass of the object C) when a force acts on an object, its acceleration is in the same direction as the force D) when a force is applied on an object, there is an equal force applied by the object in the opposite direction 8. __________ measures an object's tendency to resist changing its motion. Need a Hint? A) Gravity B) Acceleration C) Mass D) Inertia 9. A ball is thrown straight up in the air. According to Newton's first law of motion, what is the reason for the ball falling back to Earth? Need a Hint? A) A force has acted on it. B) It is accelerating in the same direction as Earth's gravitational force on it. C) The change in the ball's acceleration is proportional to the force acting on it. D) The ball exerts a force on the air surrounding it. 10. What causes a falling skydiver to slow down after the parachute opens? Need a Hint? A) air resistance B) gravity C) inertia D) reference motion 11. Which of the following types of friction keeps an object at rest? Need a Hint? A) static B) rolling C) sliding D) mobile