Atomace's Integrated Science Project

QUESTIONS:

A. What is inertia?

B. When do we consider that a moving object is at constant velocity?

C. What does the second law explain?

D. How does mass affect the acceleration of the object and its effect on the amount of force?

E. How does force affect acceleration? What is their relationship?

F. What can you say about the force you exerted when you push the door and the force exerted by the door on you?

G. How do laws of motion explain rocket propulsion?

H. What is the reason why a magician could pull a table cloth without any trampling or movement of wine glass and candle?

I. What happens if we step off a boat onto the bank of a lake?

J. Why is the law of acceleration considered the most powerful law among the three?

K. Cite a practical application of inertia in our daily life.

ANSWERS:

A. in·er·tia (ĭ-nûr'shə)
Ace's answer:
Physics. The tendency of a body to resist acceleration; the tendency of a body at rest to remain at rest or of a body in straight line motion to stay in motion in a straight line unless acted on by an outside force.
Jessica's answer:
Resistance or disinclination to motion, action, or change: the inertia of an entrenched bureaucracy.
Karen's answer:
That property of matter which manifests itself as a resistance to any change in the motion of a body. Thus when no external force is acting, a body at rest remains at rest and a body in motion continues moving in a straight line with a uniform speed (Newton's first law of motion). The mass of a body is a measure of its inertia.
My answer:
Inherent property of a body that makes it oppose any force that would cause a change in its motion. A body at rest and a body in motion both oppose forces that might cause acceleration. The inertia of a body can be measured by its mass, which governs its resistance to the action of a force, or by its moment of inertia about a specified axis, which measures its resistance to the action of a torque about the same axis.
Divine's answer:
The natural force in matter that makes it stay at rest or keep moving in a fixed direction unless acted upon by an outside force.

B. If there is no net force resulting from unbalanced forces acting on an object (if all the external forces cancel each other out), then the object will maintain a constant velocity.

C. The second law explains how the velocity of an object changes when it is subjected to an external force. The law defines a force to be equal to change in momentum (mass times velocity) per change in time. Newton also developed the calculus of mathematics, and the "changes" expressed in the second law are most accurately defined in differential forms. (Calculus can also be used to determine the velocity and location variations experienced by an object subjected to an external force.) For an object with a constant mass m, the second law states that the force F is the product of an object's mass and its acceleration a:
F = m * a
For an external applied force, the change in velocity depends on the mass of the object. A force will cause a change in velocity; and likewise, a change in velocity will generate a force. The equation works both ways.

D. The acceleration (a) of your friend's motion is dependent on the force you push (F) and his or her mass (m).We conclude that if your mass is greater than that of your friend, the acceleration of him/her would be twice as yours. Hence, the amount of force would be the same.

E. The action-reaction law also applies to the force of gravity, especially combined with Newton's Law of Dynamics. If you jump off a ladder, the force of gravity will pull you to the Earth according to F = m*g, where m is your mass and g is the acceleration due to gravity.
But that same force is working in an opposite direction on the Earth, pulling it toward you according to F = M*G, where M is the mass of the Earth and G is its acceleration. Since the mass of the Earth is so much greater than your mass, its movement is extremely small.

F. Trick Question! Each force is the same size. For every action, there is an equal ... (equal!). The fact that the door exerts a force on you only means that with its smaller mass, it is less able to withstand the larger acceleration resulting from the interaction.

G. Rocket propulsion systems provide forces to a flight vehicle and cause it to accelerate (or decelerate), overcome drag forces, or change flight direction.

H. A magician could pull a