Two students get in an elevator on the ground floor and ride the elevator up to the fifth floor?
Describe what happens to their velocity and acceleration during the trip.
Would their velocity be increasing? There would be upward acceleration at first and then there would be downward acceleration at the end right?
Yes to your answer:
"There would be upward acceleration at first and then there would be downward acceleration at the end". During the middle of the trip, velocity would be constant. It takes about one floor to reach a constant velocity, or decelerate; this varies with the elevator. Some (especially high rise ones) accelerate faster and reach a higher velocity than others
When the students enter the elevator and start moving upwards, their velocity initially increases. This is because they are gaining speed while going up, so their velocity is becoming more positive.
At the same time, there is an upward acceleration acting on the students. This acceleration is caused by the net force acting on them due to the elevator pushing them upwards. The acceleration and velocity have the same sign when the elevator is moving upwards, so they both increase at the beginning of the trip.
As the elevator approaches the fifth floor and starts to slow down, there is a change in the acceleration. The students will experience a downward acceleration, which means that the acceleration and velocity now have opposite signs. This is because the upward net force on the students decreases, causing them to decelerate or slow down.
Eventually, when the elevator reaches the fifth floor, its velocity becomes zero. The students come to a stop and their velocity changes from positive to zero. At this point, they experience zero acceleration.
So to summarize, during the trip in the elevator:
- The velocity of the students increases while the elevator is moving upwards.
- At the same time, there is an upward acceleration.
- As the elevator approaches the fifth floor, the velocity decreases and becomes zero.
- The acceleration changes from upward to downward, causing a deceleration.
- When the elevator reaches the fifth floor, the velocity becomes zero and the acceleration is also zero.