Answer:
Explanation:
Force needed to apply start the box is greater than the force needed to keep it moving because static friction is greater than the kinetic friction .
A threshold force is needed to move the box and when box started to move kinetic friction comes into play.
Friction force is directly related to the weight of the box as the friction force is
coefficient of friction time Normal reaction .
And Normal reaction is equal to the weight of box if no force is applied.


Answer: you would use a thermometer
Explanation: why a thermometer? Because a thermometer is the only way a solution can be measured in the context of temperatures. By only way, I mean the hold of the device mentioned in the question
To solve this problem it is necessary to use the concepts related to pressure and pressure, absolute and atmospheric.
Average arterial pressure in the hands,

Where,
P = Pressure
h = height (at this case the length of the arm)
Replacing with our values




Where,


Therefore the pressure is 146.765mmHg
Explanation:
Given , F = 30N and mass m = 90kg
°•° F = ma
=> a = F/m
=> a = 30/90
=> a = 1/3m/s^2