AP Physics U6

Krot

½ Iw²

Area under torque - theta curve is…

work done

W can equal..

change in KE rot

Area under sum of torque vs change in time graph is…

Equal to change in L (angular momentum)

L of system =

sum of L on all objects

Angular mom is conserved when…

no external torque is exerted

Angular speed of a non-rigid system may change w/o angular mom of system changing if…

the system changes shape by moving mass closer or further from rot. axis

When describing rolling w/o slipping system

use change in x = rtheta, v = rw, a = ra

Systems w increase in inertia rot have more KE ___ in their…

rotational, KE total

Angular mom of satellite and ME total is constant in…

circular + elliptical orbits

To find the escape velocity of an object from earth…

GPE must equal KE (1/2MV² = GMm/r)

L=mvr for…

coordinate system with object moving perp to radius, perpendicular line joins direction of v to x-axis

Object rolling down frictionless plane has no…

KE rotational

Rolling w slipping means…

• Kinetic friction acts on it

• Mechanical energy is lost as thermal

PE and KE is not constant in a satellite with an ___ orbit. It is constant with a ____ orbit.

elliptical, circular

Linear momentum of satellites in either orbit are…

not constant! direction constantly changes!!!!

The total translational kinetic energy of the spheres is equivalent to the total rotational kinetic energy of the system when…

rods are massless and spheres move at velocity v=rw

r in L = rmvsin(theta) is…

The vector from the axis of rotation to the center of mass of a particle

r1v1=r2v2 is only used for…

circular orbits

The ___ distance travelled by two attched wheels is the same!

linear

Uniform sliding w/o rolling require what 2 things?

• Balanced x and y forces (net = 0)

• Net torque = 0