Lifts Flashcards
What happens if the tension is greater than the weight of the life?
Fnet is up and acceleration is upwards.
T-w = ma
The lift could be moving up getting faster, or moving down getting slower.
What happens when weight is greater than the tension?
Fnet is down and acceleration is downwards.
w-T = ma
The lift could be moving down getting faster, or moving up getting slower.
What happens when Tension is equal to weight?
Fnet is zero and there is no acceleration.
Fnet = 0 = T-w = w-T
The lift could either be moving up or down at constant velocity or it could be stationary.
What happens if the cable snaps?
The lift is in free fall. In this situation, we can say the lift is weightless as the lift is falling and we have no sensation of weight, even though the gravitational force is still acting on the lift.
What happens when a person stands on bathroom scale within a lift?
The reading on the scale changes according to the movement of the lift.
What must we note when solving lift problems?
Apply Newton ll to each object in turn. When calculating values for the entire lift one must include the mass of all the items within the lift as well as the mass of the lift cage. Lastly, remember that the accelerations of all the objects within the lift are the same as the lift itself.
