# Physics Spring Balance problem?

In each of the following cases, state how the various readings of spring balance will compare if the balance is attached to the top of an elevator and supports a constant mass. State the answer for the following cases:

1.)Elevator at rest

2.)Moving with constant speed upward

3.)Moving with constant speed downward

4.) Moving upward with steadily increasing speed

5.)Moving upward with steadily decreasing speed

6.)Moving downward with acceleration g (g=9.8m/s2)

Relevance

In each of the following cases, state how the various readings of spring balance will compare if the balance is attached to the top of an elevator and supports a constant mass. State the answer for the following cases:

The spring expands and contracts as an external force is exerted on it.

As the elevator accelerates upward, the spring balance, which is attached to the top of an elevator, will accelerate upward. As the spring balance accelerates upward, the object that is attached to the spring will accelerate upward. The product of the mass of the object and the upward acceleration of the object will produce a force that will cause the spring to expand, so the reading of the spring balance will increase.

As the elevator accelerates downward, the spring balance, which is attached to the top of an elevator, will accelerate downward. As the spring balance accelerates downward, the spring will contract, so the reading of the spring balance will decrease.

Constant speed and at rest means the no acceleration.

No acceleration means no force to cause the spring to expand or contract.

No expansion or contraction of spring means no change of reading.

1.)Elevator at rest

2.)Moving with constant speed upward

3.)Moving with constant speed downward

4.) Moving upward with steadily increasing speed

5.)Moving upward with steadily decreasing speed

6.)Moving downward with acceleration g (g=9.8m/s2)

If you hold the spring balance in air, the reading will be the weight of the object, which is caused by the gravitational force between the earth and the object.

if you release the spring balance, the spring balance, the spring, and the object will free fall to the floor. As they free fall to the floor, their velocity will increase 9.8 m/s each second.

Free fall means no external force is being exerted on the entire system.

So all 3 parts of this system are accelerating downward at the same magnitude, the spring will not expand or contact. The reading of spring balance will remain constant.

• The spring balance will only be inaccurate when there is acceleration [assuming it is accurate to begin with].

Which have acceleration ? 4,5,6

1,2,3 have no acceleration so will all be same.

4 will show a weight proportional to unaccelerated weight x [g+a]/g

5 will be [g-a]/g

6 will be zero; that's free fall

• 1.)some initial reading I will call Ro

2.)Ro

3.)Ro

4.) >Ro

5.)<Ro

6.) 0

• Anonymous
3 years ago

I want to know this too