Download 16. Elevator worksheet 1

Elevator Lab: Worksheet 1
Name: __________________
LT: 1) Define apparent weight 2) I know how the free body diagrams change in an elevator.
Before starting this worksheet, we will have to observe the changes to the weighing scale as we go down and
up an elevator. To achieve this, I will give you the elevator pass and you will be allowed to ride the elevator
while standing on a scale. Observe and complete the following:
1. Measure and write your weight when the elevator is stationary: __________________
Observation:
Downward motion:
2. What happens to your weight when the elevator starts to accelerate down?
3. What happens to your weight when the elevator is in the middle (while going down)?
4. What happens to your weight when the elevator starts to slow down just before coming to a stop?
Upward motion:
5. What happens to your weight when the elevator starts to accelerate upwards?
6. What happens to your weight when the elevator is in the middle (while going up)?
7. What happens to your weight when the elevator starts to slow down just before coming to a stop?
Analysis and understanding of forces and the net force:
8. Draw the free body diagram as the elevator starts and reaches the ground floor.
(At the top)
(In the middle)
(Just before it comes to stop)
Type of motion: ____________
Type of motion: _____________
Type of motion: _____________
Fg=____________________
Fg=________________
FN= ________(apparent weight)
FN= ________(apparent weight)
Fnet = ______________
Fnet = ______________
Fg = _______________
FN= ________(apparent weight)
Fnet = ______________
9. Draw the free body diagram as the elevator starts from the ground floor and reaches the top.
(At the bottom)
(In the middle)
(At the top)
Type of motion: ____________
Type of motion: _____________
Type of motion: _____________
Fg=____________________
Fg=________________
FN= ________(apparent weight)
FN= ________(apparent weight)
Fnet = ______________
Fnet = ______________
Fg = _______________
FN= ________(apparent weight)
Fnet = ______________
Problem Solving
1. An elevator is moving up at a constant velocity of 2.5 m/s, as illustrated in the diagram below: The man
has a mass of 85.0 kg.
a. Construct a force diagram for the man.
b. What force does the floor exert on the man?
2. The elevator now accelerates upward at 2.0 m/s2.
a. Construct a force diagram for the man.
b. What force does the floor now exert on the man?
3. Upon reaching the top of the building, the elevator accelerates downward at 3.0 m/s2.
a. Construct a force diagram for the man.
b. What force does the floor now exert on the man?
4. While descending in the elevator, the cable suddenly breaks. What is the force of the floor on the man?
5. Consider the situation where a person that has a mass of 68 kg is descending in an elevator at a constant
velocity of 4.0 m/s. At some time "t", the elevator starts to slow to a stop at the rate of 2.0 m/s2.
If the person in the elevator were standing on a bathroom scale calibrated in Newtons, what would the
scale read while the elevator is:
(a) Descending at constant speed. Explain.
(b) Slowing to a stop? Explain.