A 2.8-kg block is hanging stationary from the end of a vertical spring that is attached to the ceiling. The elastic potential energy of the spring/mass system is 1.2 J. What is the elastic potential energy of the system when the 2.8-kg block is replaced by a 5.4-kg block?

The elastic spring energy is related to distance stretched squared. But distance stretched is proportional to force.

Here force doubles, so distance stretched doubles, so PE in the spring doubles squared.

To find the elastic potential energy of the system when the 2.8-kg block is replaced by a 5.4-kg block, we need to use the equation for elastic potential energy.

Elastic potential energy (E) = 0.5 * k * x^2

Where:
- E is the elastic potential energy
- k is the spring constant
- x is the displacement from the equilibrium position

Since the two blocks are hanging stationary in equilibrium, the displacement is the same for both cases.

First, let's find the spring constant for the 2.8-kg block case.

E = 0.5 * k * x^2

Rearranging the equation, we get:

k = 2E / x^2

Substituting the given values:

k = 2 * 1.2 J / x^2

Next, let's find the elastic potential energy for the 5.4-kg block case.

Elastic potential energy (E2) = 0.5 * k * x^2

Substituting the new mass (5.4 kg) and the spring constant we found:

E2 = 0.5 * (2 * 1.2 J / x^2) * x^2

Simplifying the equation:

E2 = 1.2 J

Therefore, the elastic potential energy of the system when the 2.8-kg block is replaced by a 5.4-kg block is 1.2 J.

To find the elastic potential energy of the system when the 2.8-kg block is replaced by a 5.4-kg block, we need to use the formula for elastic potential energy:

Elastic Potential Energy = (1/2) * k * x^2

Where:
- k is the spring constant
- x is the displacement from the equilibrium position of the spring (in this case, the extension or compression of the spring due to the hanging block)

In this problem, we are given the elastic potential energy (1.2 J) and the mass of the original block (2.8 kg). We need to find the spring constant and use it to calculate the elastic potential energy when the block is replaced.

First, let's find the spring constant (k).

We know that the elastic potential energy (E) is given by:

E = (1/2) * k * x^2

Rearranging the formula, we get:

k = (2 * E) / x^2

We are given the elastic potential energy (E) as 1.2 J, and we need to find the spring constant (k). We also need to consider that the displacement (x) remains constant in this scenario.

Next, let's substitute the given values into the formula and solve for k:

k = (2 * 1.2 J) / x^2

Now, let's find the elastic potential energy (E2) when the 5.4-kg block is used. However, we need the value of x, the displacement of the spring in this scenario.

Since we have not been given any additional information about how the spring behaves or the displacement values, we cannot determine the new elastic potential energy without further information.

To find the elastic potential energy for the new system, we either need to know the value of x with the 5.4-kg block or have additional information about the behavior of the spring.

Therefore, without knowing the displacement value or having more information, we cannot calculate the elastic potential energy of the system when the 2.8-kg block is replaced by a 5.4-kg block.