1.
Energy cannot be created or destroyed. but can be changed from one form to another.
Correct Answer
A. True
Explanation
This statement is a basic principle in physics known as the law of conservation of energy. It states that energy cannot be created or destroyed, only transformed from one form to another. This means that the total amount of energy in a closed system remains constant. Therefore, the given answer "True" is correct.
2.
________________ converts the energy of falling water into electricity.
Correct Answer
A. Hydroelectric plants
Explanation
Hydroelectric plants convert the energy of falling water into electricity. This is achieved by harnessing the kinetic energy of flowing or falling water and using it to turn turbines, which in turn generate electricity. Water is directed through large pipes or channels, and as it flows, it spins the turbines. This rotational motion is then converted into electrical energy using generators. Hydroelectric power is a renewable and clean energy source, as it relies on the natural water cycle and does not produce harmful emissions.
3.
________________ ferment farm waste and unwanted plants to produce methane gas.
Correct Answer
C. Biomass
Explanation
Biomass refers to the process of using organic materials such as farm waste and unwanted plants to produce methane gas. This process involves the decomposition of these materials through a natural fermentation process, which results in the production of methane gas. Hydroelectric plants generate electricity using the power of flowing water, while wind power harnesses the energy of wind to generate electricity. Therefore, biomass is the correct answer as it specifically relates to the process of fermenting organic materials to produce methane gas.
4.
________________converts energy of steam that comes from hot rock layers into electricity.
Correct Answer
D. Geothermal
Explanation
Geothermal energy is generated by harnessing the heat from the Earth's hot rock layers. This energy is then used to convert steam into electricity. Unlike hydroelectric plants that use flowing water, wind turbines that rely on wind power, or biomass plants that burn organic materials, geothermal power plants tap into the Earth's natural heat to produce electricity. Therefore, geothermal is the correct answer as it specifically refers to the conversion of steam from hot rock layers into electricity.
5.
A force is push or pull that can cause an object to move, change its speed and direction and change its shape or size.
Correct Answer
A. True
Explanation
A force is defined as a push or pull that can cause an object to move, change its speed and direction, and also change its shape or size. This statement accurately describes the nature and effects of a force, making the correct answer true. Forces are responsible for any kind of motion or deformation in objects, and understanding their properties is crucial in the study of physics and mechanics.
6.
An unbalanced force can change the motion of an object.
Correct Answer
A. True
Explanation
An unbalanced force can change the motion of an object because it causes a net force on the object, resulting in acceleration. According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Therefore, when an unbalanced force acts on an object, it can cause it to speed up, slow down, or change direction, altering its motion.
7.
_____________ is the tendency of an object to resist any change in its state of motion.
Correct Answer
B. Enertia
Explanation
Inertia is the tendency of an object to resist any change in its state of motion. This means that an object at rest will stay at rest, and an object in motion will continue moving at a constant velocity, unless acted upon by an external force. Inertia is a property of matter and is related to an object's mass. It is the reason why we feel a force pushing us backwards when a moving vehicle suddenly stops.
8.
_____________ are forces in opposite directions and equal in size.
Correct Answer
A. Balanced forces
Explanation
Balanced forces refer to two forces that are equal in magnitude and opposite in direction. When balanced forces act on an object, they cancel each other out, resulting in no net force and therefore no acceleration. This means that the object will either remain at rest if it was initially at rest, or continue moving at a constant velocity if it was already in motion. In other words, the forces are balanced because they counterbalance each other, resulting in a state of equilibrium.
9.
Acceleration increases as force applied on an object increases.
Correct Answer
A. True
Explanation
According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force applied on it. This means that as the force applied on an object increases, its acceleration will also increase. Therefore, the statement "Acceleration increases as force applied on an object increases" is true.
10.
Acceleration decreases as the mass of the object decreases.
Correct Answer
B. False
Explanation
The statement is false because acceleration is actually inversely proportional to the mass of an object. This means that as the mass of an object decreases, its acceleration increases. This can be explained by Newton's second law of motion, which states that the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. Therefore, if the mass decreases while the force remains constant, the acceleration will increase.
11.
The object at rest will remain at rest and an object in motion will continue to be in constant motion unless an external force acts on it.
Correct Answer
A. True
Explanation
This statement is known as Newton's First Law of Motion, also called the law of inertia. It states that an object at rest will stay at rest, and an object in motion will continue moving in a straight line at a constant speed, unless acted upon by an external force. In other words, objects tend to resist changes in their state of motion.
12.
Boys of the same weight are pushing a box against each other.
Correct Answer
A. Balanced
Explanation
The given answer "balanced" is correct because if the boys are of the same weight, it means they have equal force being applied in opposite directions. This creates a state of equilibrium where the forces cancel each other out, resulting in no net force on the box. Therefore, the box will remain stationary or move with a constant velocity, indicating a balanced situation.
13.
If force is zero.
Correct Answer
C. Enertia
Explanation
If the force is zero, it means that there is no net force acting on the object. In such a scenario, the object will remain at rest or continue to move with a constant velocity, depending on its initial state. The term "enertia" is likely a misspelling or a typo for "inertia." Inertia is the property of an object to resist changes in its motion, and in this context, it would be applicable as the object would continue its state of rest or uniform motion due to its inertia.