Mechanics

Q: What is the difference between non-uniform and uniform circular motion? A: The short answer is: Uniform Circular motion has a constant angular velocity (constant linear speed) and Non-Uniform Circular motion has a angular velocity (linear speed) changing with time. Depending on the directions of angular velocity and angular acceleration, Non-Uniform circular motion could be […]

Q: The driver steps on the brake, so the car skids downward to a full stop on a slope. What forces have done non-zero work in the slowing down motion? Is the work done by each force positive or negative?I had included the negative work done by kinetic friction. The solution includes the positive work

Q: Why does normal force do zero work? A: Work is the dot product of Force vector and Displacement vector. See my post about the operations of vector for dot product on https://www.physicsdoable.com/posts/2020-11-06-highlights-of-questionanswer/As seen in the picture, Normal force is always perpendicular to the contact surface, while the Velocity (Displacement) is always parallel to the

Q: I was wondering which equations of Circular Motion will be provided in quiz/exam. Also, could you review how to derive certain circular/orbiting motion equations that we might need to use in quiz/exam from the equations given. Like the period equation: T^2=(4pi^2r^3)/(GM)But I am confused on how to get to this equation. A: The equations

Q: When a car is rounding a banked curve (the surface of the road is angled), what type of friction is there between the car and the road that helps create the Fc and what direction is the friction pointing? I am slightly confused. As I know the car is moving, so wouldn’t the friction

Q: I have trouble figuring out what force is nonzero and what force is zero. Additionally, I would like to clarify how the forces are negative or positive when an object is speeding up or slowing down — how do these factors influence the forces? I assume that forces like friction and weight are negative

Q: How are coefficients of friction determined? I know that they are given in problems, but how would a physicist go from having a surface to figuring out its kinetic/static/rolling friction coefficient? Is there a tool that they use to measure something? A: For Kinetic and Static friction coefficients, the principle is simple and the

Q: How do we know what type of energy the problem is talking about? I don’t really understand the difference between Kinetic, Mechanical, Conservative, Potential Energy’s difference other than they have different equations. I’m confused about how to determine the differences in the types of energy and how to know which one to solve for

Q: How do we know if/when an object’s momentum has changed? Or do we always assume it’s constant because of the Law of Conservation of Momentum? Are there any special cases where this doesn’t apply? A: According to the Impulse-Momentum Theorem, the momentum of an object or a system (multiple objects) changes if an impulse

Q: Are there any key words to look for in a problem when trying to figure that out? A: In general, there are always Key Words that can help you interpret the texts and identify the problems. However, those key words vary from a topic to another. We have to learn how to recognize them