A cook holds a 1.90 kg carton of milk at arm's length. What force B must be exerted by the biceps muscle?
Wouldn't that depend on how the muscle is attached? Draw a lever drawing..
To determine the force B that must be exerted by the biceps muscle, we can use Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration. In this case, the carton of milk is not accelerating, so the net force acting on it is zero.
1. Start by drawing a free-body diagram for the carton of milk. The only two forces acting on the carton are:
- Force B, which is exerted by the biceps muscle and points upward.
- The force due to gravity (weight), which acts downward and has a magnitude of (mass of the carton) × (acceleration due to gravity).
2. Since the carton is at rest, the forces must balance each other. So, the force exerted by the biceps muscle (B) must be equal in magnitude and opposite in direction to the force due to gravity.
3. Determine the mass of the carton of milk. It is given as 1.90 kg.
4. Determine the acceleration due to gravity. It is approximately 9.8 m/s².
5. Calculate the force due to gravity: (mass of the carton) × (acceleration due to gravity).
Force due to gravity = 1.90 kg × 9.8 m/s² = 18.62 N.
6. Since the force exerted by the biceps muscle is equal in magnitude and opposite in direction to the force due to gravity, the force B is also 18.62 N.
Thus, the cook must exert a force of 18.62 N with their biceps muscle to hold the 1.90 kg carton of milk at arm's length.