Newton's 3 Laws of Motion Review

Which of the following statements are true of an object that experiences balanced forces (or unbalanced forces)?

*1. Unbalanced forces cause objects to move.

Which of the following statements are true of the concept of force?

1. A force is a push or pull exerted upon an object which results from the interaction of that object with its environment. 2. An object can experience two or more forces and not accelerate 3. A contact force results from the physical contact between two objects. 4. A force is a vector quantity; there is always a direction associated with it.

Which of the following statements are true of inertia?

1. All objects have inertia. 2. A more massive object has more inertia than a less massive object.

Consider Newton's first law of motion to determine which of the following statements are true?

1. Newton's first law of motion is applicable to both moving and non-moving objects. 2. It would take an unbalanced force to cause an object to accelerate from rest.

Which of the following statements are true of the quantity weight?

1. The weight of an object is dependent upon the value of the acceleration of gravity. 2. Weight refers to a force experienced by an object. 3.The weight of an object would be less on the Moon than on the Earth 4.The weight of an object is equal to the force of gravity acting upon the object.

Which of the following statements are true of the quantity mass?

1.The standard metric unit of mass is the kilogram. 2.Mass depends on how much stuff is present in an object 3.People in Weight Watcher's are really concerned about their mass (they're mass watchers) 4.If all other variables are equal, then an object with a greater mass would have a more difficult time accelerating. 5. If all other variables are equal, then it would require less exerted force to stop a less massive object than to stop a more massive object. 6. The mass of an object is mathematically related to the weight of the object.

Big Bubba has a mass of 100 kg on the earth. What is Big Bubba's mass on the moon where the force of gravity is approximately 1/6-th that of Earth's?

100 kg - Mass is a quantity which is independent of the location of the object. So if Big Bubba has a mass of 100 kg on Earth, then he also has a mass of 100 kg on the moon. Only the weight would change as Big Bubba is moved from the Earth to the moon. He weighs ~1000 N on Earth and 1/6-th this value (~167 N) on the moon.

Little Billie weighs 360 N on Earth. What is Little Billie's mass on the moon where the force of gravity is approximately 1/6-th that of Earth's?

36 kg - The mass of an object is related to weight by the equation W = m•g where g = ~10 m/s/s on Earth and one-sixth this value (~1.67) on the moon. So if Billy weighs 360 N on Earth, then his mass is approximately ~36 kg. His mass on the moon will be the same as his mass on Earth. Only his weight changes when on the moon; rather than being 360 N, it is 60 N. His weight on the moon could be found by multiplying his mass by the value of g on the moon: (36 kg) • (9.8/6 m/s/s) = ~60 N

As you sit in your chair and study your physics (presuming that you do), the force of gravity acts downward upon your body. The reaction force to the force of the Earth pulling you downward is _

The force of your body pulling the Earth upwards. - The force of the chair pushing you upward. As you sit in your chair, the chair is indeed pushing you upward but this is not the reaction force to the force of the Earth pulling you downward. The chair pushing you upward is the reaction force to you sitting on it and pushing the chair downward. To determine the action-reaction force pairs if given a statement of the form object A pulls X-ward on object B, simply take the subject and the object in the sentence and switch their places and then change the direction to the opposite direction (so the reaction force is object B pulls object A in the opposite direction of X). So if the Earth pulls youdownward, then the reaction force is you pull the Earthupward.

According to Newton's third law, every force is accompanied by an equal and opposite reaction force. The reason that these forces do not cancel each other is ____.

The two forces act upon different objects; only forces on the same object can balance each other.