CK-12-Physics - Intermediate

http://www.ck12.org Chapter 8. Angular Motion and Statics

FIGURE 8.16

Using Equation 2, we can useTyto solve forHy

→Hy+Ty−Ws−Wr= 0 →Hy=− 168 N+ 100 N+ 80 N= 12 N

Using Equation 1 we can solve forHxby findingTx.

Let us resolve the components of the tensionT:

Ty=TsinθandTx=TcosθorTy=Tsin 60◦andTx=Tcos 60◦

SinceTy= 168 N, we can solve forT→ 168 =Tsin 60◦→T=sin 60^168 N◦= 193. 99 → 194 N

Finally, using Equation 1 we haveTx=Hx→Tcos 60◦=Hx→( 194 N)( 0. 50 ) = 97 N

Thus(Hx,Hy) = ( 97 N, 194 N)

http://demonstrations.wolfram.com/ForcesActingOnALadder/

1. Angular momentum is defined as the product of rotational inertia and angular velocity.


2. Torque is defined asτ=rFsinθ, where the angleθis the angle between the lever armrand forceF. The
   symbol for torque is the Greek letter tau(τ)


3. By definition a counterclockwise torque is positive and a clockwise torque is negative.


4. Two conditions of equilibrium:
   i. Translational equilibrium:∑F=Fnet= 0
   ii. Rotational equilibrium:∑τ=τnet= 0