Your hand holds a litter of milk while your arm is bent at the elbow in a 90 degree angle. Estimate the torque caused by the milk on your arm about the elbow joint. Indicate all numbers used in your calculations.

A litter? Well you're going to need the weight of a litter of milk and you'll multiply that by the length of your forearm.

To estimate the torque caused by the milk on your arm about the elbow joint, we need to consider two factors: the weight of the milk and the lever arm or distance from the pivot point (elbow joint) to the point where the weight acts.

Let's assume the weight of the milk is 1 kilogram and the distance from the pivot point to the point where the weight acts is 0.5 meters.

The torque formula is: Torque = Force x Lever Arm

1. First, we need to calculate the force. The force can be determined by multiplying the mass of the milk (1 kg) by the acceleration due to gravity (approximately 9.8 m/s^2).
Force = mass x acceleration due to gravity
Force = 1 kg x 9.8 m/s^2
Force = 9.8 N (Newton)

2. Next, we multiply the calculated force by the lever arm to get the torque.
Torque = Force x Lever Arm
Torque = 9.8 N x 0.5 m
Torque = 4.9 Nm (Newton-meter)

Therefore, the torque caused by the milk on your arm about the elbow joint is approximately 4.9 Newton-meters.