Tension in Pendulum?

Question

a 0.44 kg pendulum bob passes through the lowest part of its path at a speed of 3.10 m/s. the pendulum cable is 80 cm long.

a.) what is the tension in the cable at the lowest part? 9.6 N (alread figured this part out)
b.) when pendulum reaches highest point, what angle does the cable make with the vertical? 67 degrees (got this part too)

HERE'S WHAT I DON'T KNOW:

c.) what is the tension in the pendulum cable when the pendulum reaches its highest point?

Answer 1

The tension is not zero as the previous responses suggested, although the centripetal force contribution to it is.

At the top of the arc, the acceleration is perpendicular to the cable (since the velocity starts out zero, the acceleration is in the same direction as the velocity an instant later).

In other words the total net force on the pendulum bob along the direction of the cable must be zero --> The tension is equal and opposite to the gravitational force in this direction:

F = mg cos(theta) = .44 * 9.8 * cos(67) = 1.68

Answer 2

at the highest point the weight of the bob is mg along the vertical direction , so its horizontal component is zero.
Consequently, the tension in the string is zero.

Answer 3

you like the size of the rope (r) Taking g @ 9.8 m/s/s mass (m) = sixty 3 kg velocity (v) = 2.5 m/s a) stress (newtons) simply by gravity = m * g = sixty 3 * 9.8 = 617.4 b) stress (newtons) simply by centripetal acceleration = m * v^2 / r = ? Then upload a to b

Answer 4

should be zero as all movement stops momemtarily as it starts to fall again