Circular Motion Flashcards
When a string is attached to the ball and the ball moves in a horizontal circle, does the string exert a force on the all? If so, in what direction is the force always directed?
Yes the string exerts the centripetal force perpendicular and towards the path of motion.
While the string is attached to the ball and the ball moves in a horizonal circle, does the force change either or both the direction and speed of the ball?
The centripetal force only changes the direction and velocity of the ball. Speed remains constant.
According to Newton’s first law, what type of motion should result when the string is released?
ignoring gravity and friction due to air, Newton’s first law dictates that the ball will travel in a straight line at a constant velocity unless otherwise acted upon by an external force
When a ball is twirling at a uniform speed on the end of a string, the inward force is zero. Is this statement true or false?
False; centripetal force is required to keep the ball in orbit (motion)
An object can be accelerating while maintaining a uniform (constant) speed. Is this statement true or false?
Yes, an object can STIL BE ACCELERATING WHILE MAINTING A UNIFORM SPEED (only magnitude, accelerating includes velocity (also includes direction))
How is inward force related to speed?
Inward force is directly proportional to speed^2 (curve up)
How is inward force related radius?
Inward force is inversely related to radius (1/r)
How is inward force related to mass
Inward force is directly proportional to mass
What is the expression for inward force as a function of mass, velocity, and radius?
Fc is directly proportional to (mv^2)/r (units kg x m/s^2)
What are the two formulas for accleration?
a=change in velocity/change in time
a=change in velocity/radius
derived from Fnet = Fc
m x acceleration = (mv^2)/r
What is the direction for acceleration? velocity?
towards the center, tangent to the circle/path of motion
