Free fall problem? anyone can answer?

Question

Apparent Weight. A physics student weighing 600 N stands on a bathroom scale in an elevator. As the elevator starts moving, the scale reads 400 N.Find the magnitude of the acceleration of the elevator.
Take the free fall acceleration to be g = 9.80 m/s^2.

What is the magnitude of the acceleration if the scale reads 650 N? What direction is acceleration, down or up ?

Answer 1

When scale reads 400 N, Magnitude of acceleration = 3.27 m/s2
When the scale reads 650 N, the elevator is accelerating upwards at 0.82 m/s2.

Solution:

Let the mass of the student be M.
Acceleration = a.

Weight = M * a

Weight of the student is given as 600 N.

M * a = 600 @ a=9.80m/s2
=> M = 600/9.80 = 61.22 kg

When the scale reads 400 N,
a = 400/M = 400/61.22 = 6.53 m/s2

=> Acceleration of elevator = 9.80 - 6.53 = 3.27 m/s2

When the scale reads 650 N,
a = 650/M = 650/61.22 = 10.62 m/s2

=> Acceleration of elevator = 9.80 - 10.62 = -0.82m/s2
i.e. the elevator is accelerating upwards @ 0.82 m/s2

Answer 2

When he weighs 400 N, the elevator is accelerating down. When he weighs 650 N, in the second half of the problem, the elevator is accelerating up.

In the first part, he "loses" 1/3 of his weight to the acceleration of the elevator, so

x / 9.8 = 1 / 3

x = 3.27 m/s^2

For the second part, the physics student gains 1/12 of his weight due to acceleration, so

x / 9.8 = 1 / 12

Answer 3

i have not finished physics in a lengthy time period yet i am going to offer it a shot. you comprehend acceleration is 9.8 meters/2d squared=g. you employ that to locate the fee even as the ball hits the water because you comprehend the height of the diving board. once you locate out the fee of the ball even as hitting the water, that similar speed consists of it to the bottom of the lake. So, you locate out how lengthy it takes the ball to get to the lake, subtract that from the 4.80s and verify how a options the bottom of the lake is by employing distance=speed*time.

Answer 4

sorry, i'm not a physic's student... hihihi... u should ask the physic's student.

Answer 5

all i know is that it's going down... if it were going up, he would weigh more.

Answer 6

GUVNA!