8.6C Newton's Laws Review

Master Newton's Laws! Review inertia, force, acceleration & action-reaction with engaging scenarios.

Vocabulary Matching Term Definition Inertia An object’s resistance to a change in motion Newton's First Law The law of inertia, stating that an object at rest stays at rest, and an object in motion stays in motion until an unbalanced force acts upon it Newton's Second Law The law of force and acceleration. Expressed by the equation F=ma Newton's Third Law The law that states that for every action force there is an equal and opposite reaction force Force A push or pull that changes an object’s motion Acceleration The rate of change in an object’s velocity measured in m Use the vocabulary words from the vocabulary matching section to fill in the missing information in the passage below Sir Isaac Newton was an important English scientist who lived from 1642 to 1727, and made many significant contributions to several fields of science during his life. He may be best known for developing his Laws of Motion that describe the interaction and motion of objects when forces act upon them. In Newton’s First Law , the law of inertia is described. This law states how objects in motion have inertia , or the tendency to resist changes in motion. This law is often stated as “objects in motion stay in motion, while objects at rest stay at rest, until an unbalanced force acts upon them”. In Newton’s Second Law, Newton described the relationship between force, motion, and acceleration . This relationship can be written as the equation force=ma. It is useful to use this law to understand that objects with greater mass but equal acceleration will also exert more force. Finally, in Newton’s Third Law, the relationship between action and reaction are described. This law states that for every action there is an equal and opposite reaction. For example, if you are pushing a wheelbarrow down a path, Newton’s Third Law indicates that the wheelbarrow is pushing back on you with an equal and opposite force. Read each of the six scenarios. Consider if the scenario BEST indicates Newton's 1st, 2nd, or 3rd Law. Then sort the scenario appropriately. 1st Law (Inertia) A woman is driving her car and needs to suddenly brake because a deer crosses her path. When she slams on her brakes, she flies forward, only being stopped by her seatbelt restraint. Jessie's class is going on a field trip to a science museum 30 miles from her school. When the school bus merges onto the freeway, the speed of the bus suddenly increases and jessie is pushed back into the back of her bus seat. 2nd Law (F=ma) A large semi-truck carrying a heavy load and a small sports car both stop at a red light. The sports car requires less force to stop at the light than the large truck. Sammy and Lorita complete a lab where they are hanging objects of different masses on a spring scale. they then record the force in newtons exerted by each object. 3rd Law (Action-Reaction) A rocket is launching on a mission to the International Space Station. Upon takeoff, a large jet of fire comes from the bottom of the spacecraft towards the ground. The rocket then begins to move toward the sky. Ms. Johnson has a Newton's Cradle on her desk at work. This device consists of a series of metal spheres hanging from a support. When you lift and release one of the spheres at the end, the spheres in the middle do not move, but instead it causes the one at the other end to bounce up. This process repeats until resisting forces like friction cause it to stop. As a stunt, performers sometimes use a table, set with a tablecloth and dishes, and pull the tablecloth out from under the dishes. When performed correctly, the dishes on the table stay in place. Which best explains why the dishes remain in place instead of being pulled off with the tablecloth? The mass of the dishes is so great that they have no acceleration. The tablecloth applied an equal and opposite force onto the dishes The dishes were at rest and remained at rest because no unbalanced forces acted upon them The velocity of the dishes increased Monica is riding her favorite roller coaster at the amusement park. During a drop, Monica is pushed back into her seat with great force. Which of Newton’s Laws of Motion BEST describes why this is happening? Law of Inertia Law of F=ma Law of action-reaction None of Newton's Laws describe this scenario Joey says that in a go cart race where equal force was being applied to each go cart, he would want a heavier go cart so that it would accelerate faster. Is Joey’s statement TRUE? Yes, because the more massive object will have more force No, because both go carts would have the same acceleration because they have the same force Yes, because the more massive object will have a greater acceleration No, because with equal forces applied to each go cart, the cart with the smaller mass will have a greater acceleration An octopus can move through water by sucking in water quickly and ejecting it from a siphon. As the water sprays out of the siphon, the octopus is propelled forward. Which of Newton’s Laws of Motion BEST describes why this is happening? Law of Inertia Law of F=ma Law of action-reaction None of Newton's Laws describe this scenario A skateboard has a mass of 3 kg and accelerates at a rate of 5 m Find the amount of unbalanced force? 15N If a force of 4N moves a paper airplane with an acceleration of 8 m what was its mass? 0.5kg If a 2 kg paper airplane is pushed by the wind with a force of 5N, how fast with the paper accelerate? 2.5 m A bird has a mass of 6 kg and accelerates at a rate of 7m Find the Net Force 42N What is the mass of the object if the net force acting on it was 356N and the acceleration rate was 4 m 89kg Two forces act on a parachutist during a drop. Net force is 550N. The parachutist has a mass of 100 kg. What is the acceleration of the parachutist? 5.5 m