Answer to Question #246024 in Physics for Maui

Question

1. Since astronauts in orbit are apparently weightien, a clever method of measuring their masses is needed to monitor their man gains or losses to adjust diets. One way to do this is to exert a known force on an astronauts and measure the acceleration produced. Suppose a net external force of 50.0 N is exerted and the astronaut's acceleration measured to be 0.893 m/s², (a) calculate her mass: (b) by exerting a force on the astronaut, the vehicle in which they orbit experiences an equal and opposite force. Discuss how this would affect the measurement of the astronaut's acceleration. Proposed a method in which recoil of the vehicle is avoided.

Answer 1

(a) Find the mass with Newton's second law:

$$m=\frac Fa=56\text{ kg}.$$

(b) This would decrease the acceleration because the vehicle will move in the opposite direction according to Newton's third law.

The recoil can be avoided if the mass is measured with momentum conservation. The experiment can be conducted inside the vehicle without any impact on vehicle's acceleration if the astronaut launches something of known mass and velocity and afterwards we measure the velocity of the astronaut.