A 650g ball on the end of a light rod is rotated in a horizontal circle of 1.2m radius.Calculate the torque needed to keep the ball rotating if the air resistance exerts a force of .02N on the ball. Ignore the moment of inertia and the air resistance of the rod.
Huh?
.02*1.2
Since speed is constant, no tangential acceleration and I is not relevant and m is not relevant.
To calculate the torque needed to keep the ball rotating, we first need to understand the concept of torque.
Torque (τ) is the rotational equivalent of force and is calculated by multiplying the perpendicular force applied to an object by the distance from the axis of rotation.
In this case, the air resistance exerts a force of 0.02 N on the ball. Since the ball is rotating in a horizontal circle, the force and the torque are in the same direction.
To find the torque, we need to determine the distance from the axis of rotation to the point where the force is applied. In this case, the distance is the radius (r) of the horizontal circle.
Given that the radius (r) is 1.2 m and the force (F) is 0.02 N, we can calculate the torque (τ) using the formula:
τ = F * r
Substituting the values:
τ = 0.02 N * 1.2 m
τ = 0.024 Nm
Therefore, the torque needed to keep the ball rotating is 0.024 Nm.