What will a spring scale read for the weight of a 73 kg woman in an elevator that moves upward with constant speed of 5.4 m/s?
force= mg+ma
Note: In this case, there is zero acceleration (a)
73 kg
To determine what a spring scale reads for the weight of a 73 kg woman in an elevator moving upward with a constant speed of 5.4 m/s, we need to consider the forces acting on the woman.
First, let's understand the concept of weight. Weight is the force exerted on an object due to gravity. The formula for weight is given by W = mg, where W is the weight, m is the mass of the object, and g is the acceleration due to gravity (approximately 9.8 m/s² on Earth).
In this scenario, the woman's weight is acting downward due to gravity. However, the elevator is moving upward with a constant speed, and therefore, the net force on the woman is zero.
To calculate the normal force acting on the woman (which is the force experienced by the spring scale), we need to consider the opposing forces:
1. Weight (mg): The downward force due to gravity is given by the formula W = mg, where m is the mass of the woman (73 kg) and g is the acceleration due to gravity (9.8 m/s²). So, W = 73 kg * 9.8 m/s² = 715.4 N.
2. Normal force (N): The normal force acts in the opposite direction to the weight, pushing the woman upward. In this case, the normal force must be equal in magnitude to the weight to create a net force of zero. Therefore, the normal force should also be 715.4 N.
So, the spring scale will read 715.4 N as the weight of the 73 kg woman in the elevator moving upward with a constant speed of 5.4 m/s.