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Solving Physics Exercise 10: Potential Energy
Exercise 1 (page 141 Physics textbook grade 10)
Define and explain the meaning of potential energy:
a) Gravitational
b) Elastic
* Solution guide:
- Gravitational potential energy (also known as gravitational potential) of an object is a form of energy interaction between the Earth and the object, it depends on the position of the object in the gravitational field.
- Elastic potential energy: is the energy of an object under the influence of elastic force.
- The significance of gravitational potential energy: when an object is at a height z above the ground, the object has the ability to do work, meaning the object carries energy, this energy is stored inside the object in the form called gravitational potential energy.
- Similarly, a spring with a stiffness of k when compressed or extended by an amount Δl then the spring force can do work, meaning the object carries energy, this energy is called elastic potential energy.
Exercise 2 (page 141 Physics textbook grade 10)
When an object falls from height z, with the same initial velocity, along different paths to the ground, then?
A. The magnitude of the velocity at ground contact is the same
B. The falling time is the same
C. The work done by gravity is the same
D. The falling acceleration is the same
Please select the incorrect statement.
* Answer:
Choose B.
Exercise 3 (page 141 Physics textbook grade 10):
An object with mass 1.0 kg has potential energy 1.0 J with respect to the ground. Taking g = 9.8 m/s2. Then, how high is the object?
A. 0.102 m;
B. 1.0 m
C. 9.8 m;
D. 32 m
* Answer:
Choose A
* Solution method:
Apply the formula for calculating gravitational potential energy:
Exercise 4 (page 141 Physics textbook grade 10)
An object with mass m attached to one end of a spring with stiffness k, the other end of the spring is fixed. When the spring is compressed by a distance Δl (Δl is less than 0) then how much is the elastic potential energy?
* Answer:
Choose A
Exercise 5 (page 141 Physics textbook grade 10):
In figure 26.5, two objects of equal mass are placed at two positions M and N such that MN is horizontal. Compare the potential energy at M and at N.
* Solution guide:
Since MN lies horizontally, if we choose the same potential energy reference point (for example, at O), then the potential energy of the object at M and at N is equal.
Exercise 6 (page 141 Physics textbook grade 10):
A spring with stiffness k = 200 N/m, one end fixed, the other end attached to a small object. When the spring is compressed by 2 cm, then what is the elastic potential energy of the system? Does this potential energy depend on the mass of the object?
* Solution guide:
Apply the formula for calculating elastic potential energy:
Physics encompasses numerous formulas, among which the formula for calculating initial velocity stands as a vital piece of knowledge, applicable not only in academic studies but also in daily life. To recall this formula, you can refer to it here.
- Read more: Formula for calculating initial velocity
