Lesson 1: Newton's First Law Of Motion

Inertia is the tendency of an object to resist changes in its state of motion. This means that an object at rest will remain at rest, and an object in motion will continue moving at a constant velocity, unless acted upon by an external force. Inertia is a fundamental property of matter and is related to the mass of an object. The greater the mass, the greater the inertia, and the more force is required to change its motion. Inertia is a concept that is often observed in everyday life, such as when a car suddenly stops and passengers lurch forward due to their inertia.

Velocity is the correct answer because it refers to the speed of an object in a specific direction. It is a vector quantity that includes both magnitude (speed) and direction, making it different from speed, which only considers the magnitude of an object's motion. Therefore, velocity accurately describes the speed with a direction.

Mass is the quantity that depends solely upon inertia. Inertia is the resistance of an object to changes in its motion, and mass is a measure of this resistance. The more mass an object has, the greater its inertia and the harder it is to change its motion. Therefore, mass is the correct answer as it directly relates to the concept of inertia.

The explanation for the given correct answer is that in order to determine if the forces acting upon an object are balanced or unbalanced, it is necessary to analyze and identify the forces that are acting upon the object and the direction in which they are acting. This analysis helps in understanding the overall net force acting on the object, which determines whether the forces are balanced (resulting in no acceleration) or unbalanced (resulting in acceleration). Therefore, the statement is true.

According to Newton's first law, the rock will continue in motion in the same direction at constant speed.

Tosh is correct. Inertia is that quantity which depends solely upon mass. The more mass, the more inertia. Momentum is another quantity in Physics which depends on both mass and speed. Momentum will be discussed in a later unit.

Once the cat hits the water, the forces are balanced (50 N down and 50 N up). The cat would only bounce upwards if the water applied an upward force greater than 50 N. As stated in the problem, the water applies only 50 N of upward force. Furthermore, the upward force would first contribute to slowing the cat down (an upward acceleration) before it could begin to actually move it upward.

Galileo, a premier scientist in the seventeenth century, developed the concept of inertia. His experiments and observations challenged the prevailing belief that objects needed a force to keep moving. Galileo proposed that objects in motion would stay in motion unless acted upon by an external force, which is now known as the principle of inertia. This concept revolutionized the understanding of motion and laid the foundation for Newton's laws of motion. Galileo's contributions to physics and astronomy solidified his status as one of the most influential scientists in history.

An object is said to be acted upon by an unbalanced force when there is an individual force that is not being balanced by a force of equal magnitude and in the opposite direction. This means that if there is a force acting on an object that is not being cancelled out by an equal and opposite force, then the object will experience an unbalanced force. Therefore, the statement is true.

Once the cat hit the water, the forces are balanced (50 N down and 50 N up). The upward force of the water on the cat is balanced by the downward pull of gravity. The cat will continue in motion at constant speed.

If an object is in motion, then it will stay in motion with those very same motion characteristics. It doesn't take any force to maintain that same state of motion. In fact, the presence of a force would "ruin" such a state of motion and cause an acceleration.

Newton's First Law of Motion, also known as the law of inertia, states that an object at rest will remain at rest, and an object in motion will continue moving at a constant velocity in a straight line, unless acted upon by an unbalanced force. This means that an object will maintain its state of motion, whether it is at rest or moving, unless there is an external force causing a change in its motion. This law helps to explain why objects tend to resist changes in their motion and why it is necessary to apply force to start, stop, or change the direction of an object's motion.

Absolutely yes!

Even in space objects have mass. And if they have mass, they have inertia. That is, an object in space resists changes in its state of motion. A force must be applied to set a stationary object in motion. Newton's laws rule - everywhere!

The answer is 2. Once leaving the rim, the ball will follow an "inertial path" (i.e., a straight line). At the instant shown in the diagram, the ball is moving to the right; once leaving the rim, there is no more unbalanced forces to change its state of motion. Paths 1 and 3 both show the ball continually changing its direction once leaving the rim.

Once the cat hits the water, the forces are balanced (50 N down and 50 N up). However, an object in motion (such as the cat) will continue in motion at the same speed and in the same direction. When the cat strikes the water, it stops accelerating; yet it does not stop moving.

An object in motion will maintain its state of motion. The presence of an unbalanced force changes the velocity of the object.

Fred's inertia will increase!

Fred will increase his mass if he makes a habit of this. And if his mass increases, then his inertia increases.

Graph B is correct. The cat first accelerates with a negative (downward) acceleration until it hits the water. Upon hitting the water, the cat experiences a balance of forces (50 N downwards due to gravity and 50 N upwards due to the water). Thus, the cat will finish its motion moving with a constant velocity. Graph B depicts both the initial negative acceleration and the final constant velocity.

Tape A is correct.

The cat first accelerates with a negative (downward) acceleration until it hits the water. Upon hitting the water, the cat experience a balance of forces (50 N downwards due to gravity and 50 N upwards due to the water). Thus, the cat will finish its motion moving with a constant velocity. Diagram A depicts both the initial downward acceleration and the final constant velocity.

The answer could be A (but does not have to be A) and it could be B (but does not have to be B). An object having balanced forces definitely cannot be accelerating. This means that it could be at rest and staying at rest (one option) or could be in motion at constant velocity (a second option). Either way, it definitely is not accelerating - choice C of your four choices.