Question

with non uniform circular motion to find the acceleration of R do you do V^2/magnitude of R

Answer 1

what do you mean the acceleration of R ?
could you elaborate?

Answer 2

well i want to find the tension of the rope of the pendulum and to do that i have to take ma and im given the mass of the pendulum and length, but not the acceleration

Answer 3

and im given the velocity

Answer 4

does it say at what point it is in the swing?

Answer 5

ya as its swinging upward and it makes a certain angle with the vertical

Answer 6

all the forces along the r direction must be zero, so let's consider that

Answer 7

yep looks like what i drew

Answer 8

so along r we have the force of gravity in that direction and the centripetal force being cancelled by tension. Notice that the component of gravity along r will be the cosine of the angle that the string makes with the vertical:\[\large \sum F_r=F_{gr}+F_c-T=mg\cos\theta+m\frac{v^2}r-T=0\]this can be solved for the tension T