Aheavy steel ball is hung from a cord to make a pendulum. the ball is pulled to the side so that the cord makes a 5 ∘ angle with the vertical. holding the ball in place takes a force of 40 n . if the ball is pulled farther to the side so that the cord makes a 8 ∘ angle, what force is required to hold the ball?

64 N

Explanation:

Given that the angles are very small, the following approximation can be made:

F ≈ m*g*α

where F is the force needed to hold the ball, m is the ball mass, g is the acceleration of gravity and α is the angle between the cord and the vertical.

Let's call F1 the force needed to hold the ball at 5° (α1) and F2 the force needed to hold the ball at 8° (α2).

F1 ≈ m*g*α1

F2 ≈ m*g*α2

Dividing the equations:

F1/F2 = α1/α2

F2 = (α2/α1)*F1

F2 = (8/5)*40

F2 = 64 N

current flows in a wire