Mcat Physics Ch. 1 Kinematics & Dynamics

Vectors are quantities that have both magnitude (size) and direction. Examples of vectors include displacement, velocity, acceleration, force, etc. Having only magnitude without direction would make them scalars, not vectors.

Scalars are defined as physical quantities that have only magnitude, without any associated direction. This distinguishes them from vectors, which have both magnitude and direction.

The dot product of two vectors results in a scalar quantity, not a vector quantity. It is obtained by multiplying the magnitudes of the vectors and the cosine of the angle between them, not dividing the magnitudes. The angle between the vectors is crucial in determining the dot product.

The cross product of two vectors results in a vector, not a scalar. The cross product involves the sine, not the cosine, of the angle between the vectors. The right hand rule is used to determine the direction of the resultant vector.

Displacement is a vector quantity that refers to the overall change in an object's position. It is independent of the path taken and can be represented by the straight line distance between the start and end locations. Displacement is not the same as the total distance traveled, speed at a given moment, or acceleration due to gravity.

Distance is a scalar quantity that represents the path traveled by an object, regardless of direction or speed. It is a measure of how far an object has moved in total.

Average velocity is calculated by dividing the change in displacement (x) by the time taken (t). This formula helps determine how far an object travels over a specific period of time.

Instantaneous velocity refers to the velocity of an object at a specific moment in time, as opposed to average velocity over a given interval. The correct formula considers the limit of the change in displacement over time as the time interval approaches zero, capturing the exact velocity at that instant.

Instantaneous speed refers to the speed of an object at a particular moment in time, represented by the magnitude of its velocity vector. It is different from average speed or change in speed over time, and it does not necessarily represent the maximum speed possible.

Force is a concept related to the interaction between objects and results in acceleration, not a unit of mass, measure of distance, or amount of energy exerted.

Gravity is the natural force of attraction between any two objects with mass, and it is responsible for the phenomenon of weight. It is what keeps planets in orbit around the sun and our feet on the ground.

Friction is the force that resists motion between two surfaces in contact. It is caused by the electrostatic interactions between the molecules of the objects' surfaces, leading to opposition to motion.

Static friction is the friction force that prevents two surfaces from sliding past each other when not in motion.

Kinetic friction occurs between two objects that are in motion relative to each other, creating resistance to their relative motion. Unlike static friction, which occurs between stationary objects, kinetic friction has a constant value and is independent of the objects' speed. Therefore, the correct answer emphasizes the key characteristics of kinetic friction.

The coefficient of friction depends on the materials in contact and varies between static and kinetic friction. It is not determined by the weight of the object, nor is it uniform across all materials. Additionally, the coefficient of static friction is typically higher than the coefficient of kinetic friction.

Weight is the force experienced by a given mass due to Earth's gravity, calculated by multiplying mass by gravity. It is not a measurement of length, temperature, or speed.

Acceleration refers to the change in velocity over time, not just the speed, distance traveled, or force applied. It is a vector quantity that indicates the rate of change of velocity.

Newton's First Law, also known as the Law of Inertia, states that an object will remain at rest or in motion with a constant velocity unless acted upon by a net external force. This means that objects do not accelerate unless there is a force applied to them.

Newton's Second Law of Motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass, which is described by the formula Fnet = ma.

Newton's Third Law is often summarized as 'For every action, there is an equal and opposite reaction', but the specific details involve the interaction between two objects leading to equal and opposite forces.

Linear motion refers to the movement of an object in a straight line where the velocity and acceleration are parallel to each other. The object's path is either a straight line or a straight line down an incline with an angle. The incorrect answers do not align with the definition of linear motion, as circular paths, perpendicular velocity and acceleration, and zig-zag patterns do not meet the criteria for linear motion.

The correct value for the acceleration due to gravity near the surface of the Earth is approximately 9.8 m/s2. This value can vary slightly depending on location and altitude.

Terminal velocity is the constant speed that a freely falling object eventually reaches when the resistance of the medium it is falling through balances the acceleration due to gravity. This occurs when the drag force due to air resistance equals the weight of the object, resulting in no further acceleration.

When air resistance is negligible and terminal velocity cannot be reached, the only force acting on the falling object is gravity, which will cause it to accelerate downwards.

Projectile motion involves both x and y components due to the influence of gravity. While the y component experiences the effect of gravity changing the vertical velocity (vy), the x component remains constant. Therefore, the incorrect answers that suggest otherwise are not accurate in describing projectile motion.

Circular Motion (Uniform Circular Motion) involves an object moving at a constant speed while changing direction along a circular path. Linear Motion involves motion along a straight line, Oscillatory Motion involves repetitive back-and-forth motion, and Rotational Motion involves spinning or revolving around an axis.

Centripetal Force is the force that keeps an object in circular motion by continuously pulling it back towards the center of the circle, preventing it from moving tangentially and breaking out of the circular path.

In Translational Equilibrium, an object will neither accelerate nor decelerate, it will remain in a state of constant velocity or completely still as long as the vector sum of all forces acting on it is zero.

Translational motion refers to the movement of an object without any rotation, following a linear pathway, parabolic trajectory, or projectile motion. It does not involve rotational motion or stationary positions.