# Physical Science

## Chapter 3: Forces

### Forces

 1. What happens to the weight of astronauts when they are in orbit? Need a Hint? A) They lose weight. B) They become weightless. C) It remains the same. D) They gain weight. 2. An example of friction is __________. Need a Hint? A) a car rolling to a stop at a traffic light B) a baseball moving in a projectile motion C) a tree standing in a field D) the free fall of astronauts on the space shuttle 3. When force is increased, what happens to acceleration? Need a Hint? A) It fluctuates. B) It stays the same. C) It decreases. D) It increases. 4. Newton's third law of motion states that __________. Need a Hint? A) an object in motion tends to stay in motion B) for every action force there is an equal and opposite reaction force C) an object at rest tends to stay at rest D) force is equal to mass times acceleration 5. What is the friction between a rolling object and the surface it rolls on called? Need a Hint? A) air resistance B) rolling friction C) static friction D) sliding friction 6. When a falling object reaches terminal velocity, the force of gravity __________ the force of air resistance. Need a Hint? A) is unrelated to B) is greater than C) is less than D) equals 7. What can change when momentum changes? Need a Hint? A) mass and velocity B) neither mass nor velocity C) velocity D) mass 8. Which planet was discovered because of its gravitational pull on other planets? Need a Hint? A) Uranus B) Jupiter C) Venus D) Mars 9. Static friction occurs when two objects are __________. Need a Hint? A) moving against each other B) at rest C) colliding D) rolling 10. What is the equation for momentum? Need a Hint? A) P = m/v B) F = m x a C) P = m x v D) F = m/a 11. What happens to the gravitational force as objects get farther apart? Need a Hint? A) It decreases. B) It stays the same. C) It fluctuates. D) It increases. 12. Newton's second law of motion is __________. Need a Hint? A) A = f/m B) F = m/a C) P = m/v D) P = m x v 13. In which direction is the centripetal force? Need a Hint? A) toward the center of the circle B) along the curve C) upward D) toward the edges of the circle 14. What causes a rocket to move? Need a Hint? A) The rockets engines push against the vacuum of space. B) The rocket follows Newton's first law of motion. C) The rocket pushes away from gravity. D) The rocket's engines push exhaust gas away from it. 15. What happens to the acceleration due to gravity of an object in projectile motion? Need a Hint? A) It fluctuates. B) It decreases. C) It stays the same. D) It increases. 16. What happens to the momentum of a baseball bat when it hits a baseball? Need a Hint? A) Some of it is transferred to the baseball. B) It decreases to zero. C) All of it is transferred to the baseball. D) All of it remains in the bat. 17. What causes thrown objects to travel in a curved path? Need a Hint? A) gravity B) air resistance C) momentum D) Earth's gravitational pull and the inertia of the object 18. What causes some objects to fall slower than others? Need a Hint? A) forces B) acceleration C) air resistance D) gravity 19. A snow skier slowing to a stop after skiing down a mountain is an example of __________ friction. Need a Hint? A) rolling B) air C) static D) sliding 20. What causes acceleration to change in an object traveling in a circular path? Need a Hint? A) force changes B) momentum changes C) speed changes D) direction changes