Force Problem all my answers don't work

[liamtcarroll]

Assume you are on a planet similar to Earth
where the acceleration of gravity is approximately 10 m/s
and the positive directions for
displacement, velocity, and acceleration are
upward.
At time t = 0 s, an elevator is at a displacement of x = 0 m with a velocity of v = 0 m/s.
A student whose normal weight is 400 N
stands on a scale in an elevator and records
the scale reading as a function of time.

0-5sec------400
5-10sec-----700
10-15sec----0
15-20sec----200what is the velocity of the elevator at the end of 20 sec

 

[aralbrec]

What does the scale measure?

Maybe a hint: if the elevator and person are not moving, the force the scale applies to the person standing on it must equal what?

 

[Basic_Physics]

You need to determine the acceleration of the student during each period. Then draw a acceleration vs time graph and integrate it up to 20 s.

 

[berkeman]

Assume you are on a planet similar to Earth
where the acceleration of gravity is approximately 10 m/s
and the positive directions for
displacement, velocity, and acceleration are
upward.
At time t = 0 s, an elevator is at a displacement of x = 0 m with a velocity of v = 0 m/s.
A student whose normal weight is 400 N
stands on a scale in an elevator and records
the scale reading as a function of time.

0-5sec------400
5-10sec-----700
10-15sec----0
15-20sec----200


what is the velocity of the elevator at the end of 20 sec

Stop posting questions showing zero effort. You *must* show your attempt at a solution in your schoolwork posts. Check your PMs.

 

[Nickie]

Based on the information provided, it is not possible to accurately determine the velocity of the elevator at the end of 20 seconds. This is because the scale readings do not provide enough information about the forces acting on the elevator. In order to accurately calculate the velocity, we would need to know the mass of the elevator and the forces acting on it, such as the force of gravity and any external forces. Without this information, it is not possible to accurately solve the force problem and determine the velocity of the elevator.