# Conservation of Energy block of mass

• SamTsui86
In summary, a small block of mass m1 = 0.600 kg is released from rest at the top of a curved wedge of mass m2 = 4.50 kg, which sits on a frictionless horizontal surface. When the block leaves the wedge, its velocity is measured to be 4.00 m/s to the right. To find the height h of the wedge, conservation of energy and momentum must be considered, including the kinetic energy of the wedge.
SamTsui86
A small block of mass m1 = 0.600 kg is released from rest at the top of a curved wedge of mass m2 = 4.50 kg, which sits on a frictionless horizontal surface as in Figure P6.59a. When the block leaves the wedge, its velocity is measured to be 4.00 m/s to the right, as in Figure P6.59b.

What is the height h of the wedge?

Isn't this problem just conservation of energy
I did
KE+PE initial = KE + PE final
0 + mgh = 1/2 mv^2 + 0 and solve for h v is 4.0 m/s
9.8 h = 8
h= .82

SamTsui86 said:
A small block of mass m1 = 0.600 kg is released from rest at the top of a curved wedge of mass m2 = 4.50 kg, which sits on a frictionless horizontal surface as in Figure P6.59a. When the block leaves the wedge, its velocity is measured to be 4.00 m/s to the right, as in Figure P6.59b.

What is the height h of the wedge?

Isn't this problem just conservation of energy
I did
KE+PE initial = KE + PE final
0 + mgh = 1/2 mv^2 + 0 and solve for h v is 4.0 m/s
9.8 h = 8
h= .82
It is not just conservation of energy, and you have not accounted for all of the energy. The wedge is not stationary in this problem. What is conserved?

oh i understand now, i have to include the kinetic energy of the wedge in the formula, thank you

SamTsui86 said:
oh i understand now, i have to include the kinetic energy of the wedge in the formula, thank you
And you have to include another conservation principle

oh ok, i got the answer now, thank you

## 1. What is the conservation of energy principle?

The conservation of energy principle states that energy cannot be created or destroyed, but it can be transformed from one form to another. This means that the total amount of energy in a closed system remains constant over time.

## 2. How does the mass of an object affect its energy?

According to the law of conservation of energy, mass and energy are interchangeable. This means that the more mass an object has, the more energy it possesses. Objects with higher mass require more energy to move and accelerate, while objects with lower mass require less energy.

## 3. What is the relationship between kinetic and potential energy in a block of mass?

In a block of mass, kinetic energy is the energy an object possesses due to its motion, while potential energy is the energy an object has due to its position or state. As an object moves, its kinetic energy increases while its potential energy decreases, and vice versa. In a closed system, the total amount of kinetic and potential energy remains constant.

## 4. Can energy be lost in a block of mass?

No, according to the conservation of energy principle, energy cannot be lost in a block of mass. Energy can only be transformed from one form to another, but the total amount of energy in the system remains constant.

## 5. How does friction affect the conservation of energy in a block of mass?

Friction is a force that resists motion and can cause energy to be lost in the form of heat. This means that some of the energy in a block of mass may be transformed into heat due to friction. However, the total amount of energy in the system remains constant, as energy cannot be lost.

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