what force must the woman in Figure 3.38 exert on the floor with her hands in order to do a pushup?
Torques:
m•g•0.9 = F•1.5
F = m•g•0.9/1.5 = 50•9.8•0.9/1.5 = 294 N
To determine the force the woman must exert on the floor with her hands to do a push-up, we need some additional information such as the woman's weight and the angle at which she is performing the push-up. However, we can provide a general explanation of the forces involved in this exercise.
When a person performs a push-up, they are in a horizontal position, with their weight supported by both their hands and toes. Let's assume that the woman's body is in a straight line, parallel to the ground. In this position, there are two primary forces acting on her:
1. The force of gravity: This force is pulling the woman downwards towards the Earth. The gravitational force depends on her mass. The standard acceleration due to gravity is approximately 9.8 m/s².
2. The normal force: This force is exerted by the floor on the woman's hands. It acts perpendicular to the surface and counters the force of gravity. It prevents her from sinking through the floor. Depending on the position of her body during the push-up, the normal force may vary.
To calculate the force the woman must exert on the floor with her hands, we need to consider the equilibrium or balance of forces. In order for her to stay in a static position (not accelerating up or down), the force she exerts on the floor must equal the force of gravity acting downwards.
However, without more specific information, such as the woman's weight or the angle of the push-up, it isn't possible to provide an exact numerical value for the force she needs to exert.