Are You Ready To Take The Physics Midterm Exam Test?

The given answer, "are two different quantities," is correct because mass and weight are indeed two distinct concepts. Mass refers to the amount of matter an object contains and is measured in kilograms, while weight is the force exerted on an object due to gravity and is measured in newtons. Although mass and weight are related, they are not the same thing, as weight can vary depending on the gravitational pull, while mass remains constant regardless of the gravitational field.

From the given scenario, if you suddenly fall forward while standing in a moving bus, it implies that the bus's velocity has decreased. This is because if the velocity had increased, you would have been pushed backward instead of falling forward. If the bus was turning right or left, it would not cause you to fall forward, but rather to the side. Therefore, the only logical explanation is that the bus's velocity has decreased.

Action-reaction forces refer to a pair of forces that occur simultaneously and are exerted on two different objects. According to Newton's third law of motion, these forces are equal in magnitude but opposite in direction. This means that if one object exerts a force on another object, the second object will exert an equal but opposite force on the first object. This principle is important in understanding how objects interact with each other and is a fundamental concept in physics.

In the absence of an external force, a moving object will move with constant velocity. This is because according to Newton's first law of motion, an object in motion will continue to move at a constant velocity unless acted upon by an external force. Therefore, the object will neither slow down nor speed up, but rather maintain a steady speed and direction of motion.

When the rocket engines on the starship NO-PAIN-NO-GAIN are suddenly turned off, the starship will move with constant speed. This is because, according to Newton's first law of motion, an object in motion will continue moving at a constant velocity unless acted upon by an external force. Since there are no external forces acting on the starship in empty space, it will continue moving with the same speed it had before the engines were turned off.

When the net force applied is the same and the mass is doubled, according to Newton's second law of motion (F = ma), the acceleration will be halved. This is because the mass has increased, which means there is more inertia to overcome, resulting in a slower acceleration. Therefore, the correct answer is a/2.

When a rocket moves through empty space in a straight line with constant speed, it experiences no external forces acting on it. According to Newton's first law of motion, an object will continue to move at a constant velocity unless acted upon by an external force. Since there are no external forces acting on the rocket, no force needs to be applied to sustain its motion. Therefore, the force that must be applied to the rocket in order to sustain its motion is zero.

The first law of motion, also known as the law of inertia, states that an object at rest will stay at rest and an object in motion will stay in motion with the same speed and direction unless acted upon by an external force. This law explains why motorists should buckle-up because it highlights the importance of wearing seat belts to prevent passengers from continuing to move forward in the event of a sudden stop or collision. Seat belts provide the necessary external force to restrain the occupants and prevent them from being thrown out of the vehicle or hitting the windshield.

If the force is doubled and it acts on four times the mass, the acceleration will be halved. This can be explained using Newton's second law of motion, which states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Since the force is doubled and the mass is quadrupled, the ratio of force to mass remains the same. Therefore, the acceleration will be half of the original acceleration.

This scenario demonstrates Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. In this case, the force exerted by the first car on the second is matched in magnitude by the force exerted by the second car on the first. This principle applies to any interaction between two objects, where the forces they exert on each other are always equal and opposite.

The correct answer is the string pulling up on the toy with an 8N force. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. In this scenario, the action force is the Earth pulling downward on the toy with its weight force of 8N. The reaction force, therefore, must be the string pulling up on the toy with an equal 8N force.

When an object of mass m sits on a flat table, the Earth exerts a downward force on the object equal to its weight, mg. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. Therefore, the object pushes down on the table with a force equal to mg. As a reaction to this, the table pushes up on the object with a force equal to mg, which is the correct answer. The other options are not relevant to the forces acting on the object and the table.

The acceleration of an object is inversely proportional to its mass. This means that as the mass of an object increases, its acceleration decreases, and vice versa. This can be explained by Newton's second law of motion, which states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Therefore, if the net force acting on an object remains constant, an increase in mass will result in a decrease in acceleration.

The correct answer is Newton's third law. This law states that for every action, there is an equal and opposite reaction. When you blow up a balloon, the air pressure inside the balloon pushes against the walls of the balloon. When you release the balloon, the air rushes out in one direction, creating a force that propels the balloon in the opposite direction. This is an example of Newton's third law in action.

When you sit on a chair, the resultant force on you is zero because the force of gravity pulling you downwards is balanced by the normal force exerted by the chair pushing upwards. This equilibrium of forces creates a net force of zero, resulting in no acceleration or movement.

Action-reaction forces always act on different objects. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. This means that when one object exerts a force on another object, the second object exerts an equal and opposite force back on the first object. These forces are always exerted on different objects, not on the same object. Therefore, the correct answer is that action-reaction forces always act on different objects.

If a constant net force acts on an object, the object will experience a constant acceleration. This means that the object's velocity will change by the same amount over equal intervals of time. The object will continue to accelerate in the same direction as long as the net force remains constant. The speed of the object may or may not be constant depending on the initial conditions, but the acceleration will remain constant.

The force on the truck is equal to the force on the car because of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. When the truck collides with the car, the force exerted by the truck on the car is equal in magnitude and opposite in direction to the force exerted by the car on the truck. Therefore, the force on the truck is equal to the force on the car.

Inertia is a fundamental concept in physics that describes the inherent property of all objects to remain at rest or in uniform motion in a straight line unless acted upon by an external force. This resistance to changes in motion is why a stationary object will stay still unless pushed or pulled, and why a moving object will continue moving at the same speed and direction unless a force, like friction or gravity, acts upon it. The concept of inertia is central to Newton's laws of motion, which form the foundation of classical mechanics.