Posts

Q: I had a quick question about the particle models. If time stamps are t=1, t=2, t=3, etc. and the velocity vectors 1,2, and 3 are listed between each point, these vectors refer to AVERAGE velocity right? And since average velocity uses displacement between time stamps, a particle in the model could theoretically move back […]

Q: If velocity is zero, why wouldn’t acceleration be zero as well? Seeing that both velocity and acceleration are related and given that finding the acceleration relies on the velocity, why is the acceleration unknown at a specific time instance if the velocity is known to be zero at that time? A: Acceleration is the

Q: For conservation of momentum, what counts as an external force/impulse? Does gravity count? A: After we have defined the system of interest in a problem, for example, the 2 objects in a 2-body collision, any force/impulse from the outside of the system is considered external! Yes, gravity is external! However, the impulse of gravity

Q: At the beginning of the lecture today when explaining a fixed pulley, you mentioned there being a connection between circular motion and rotation. I am a bit confused about what exactly the relationships are between them and was wondering if you could provide me a bit more clarity about it. A: For a rotating

Q: I was wondering if an object’s linear velocity in a circular motion is always expressed as a magnitude, or if the sign depends on the direction that the object is traveling around the circle (e.g., clockwise/counterclockwise.)  A: In a circular motion, the linear velocity is always in the Tangential direction, but Tangential is actually

Q: This is a conceptual question I have wondered since high school but never asked. If every force has an equal and opposite reaction, then how come a sledgehammer is easily able to crush a grape? Going off of Newton’s third law, shouldn’t we expect to see the grape push back with just as much

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