Jhs 3 Integrated Science

The boy slipped on a banana peel because there was no friction. Friction is the force that opposes the motion of objects in contact with each other. In this case, the absence of friction between the banana peel and the ground caused the boy's foot to slide uncontrollably, leading to his fall.

Gravitational force is the correct answer because it is the force that acts between planets and keeps them in their orbits. This force is generated by the mass of the planets and is responsible for the attraction between them. Without gravitational force, planets would not be able to maintain their orbits and would either drift away or collide with each other.

When an object moves from a rough surface to a smooth one with the same energy, the frictional force acting on the object decreases. As a result, there is less resistance to the object's motion, allowing it to accelerate and increase its speed. Therefore, the correct answer is "Increases."

Engine oil in a tractor's engine serves the purpose of lubricating the engine parts. Lubrication is essential to reduce friction between moving components, preventing wear and tear, and ensuring smooth operation. It forms a protective film on the surfaces, reducing heat and preventing metal-to-metal contact. This helps in extending the lifespan of the engine and improving its overall performance.

Centripetal force is the force that acts towards the center of the circular path and is responsible for keeping an object moving in a circular path. It is necessary to counterbalance the inertia of the object, which tends to keep it moving in a straight line. Gravitational force is the force of attraction between two objects and does not necessarily cause circular motion. Inertia force is not a recognized force, and reaction force is the force exerted by an object in response to another force acting upon it, but it does not specifically cause circular motion. Therefore, the correct answer is centripetal force.

Surface tension is the force that enables light objects to rest on the surface of liquids. It is the result of cohesive forces between the liquid molecules, causing the surface to behave like a stretched elastic sheet. This force allows small objects, such as insects or small paper clips, to float on the surface of water without sinking. Surface tension is responsible for phenomena like water droplets forming spherical shapes, the ability of some insects to walk on water, and the capillary action in plants.

Kerosene is poured on the surface of a pond in order to break the surface tension. Surface tension is the force that holds the molecules of a liquid together at its surface. By pouring kerosene, which has a lower surface tension than water, it disrupts the cohesive forces between water molecules, causing the surface tension to break. This makes it easier for animals to consume the water, as they can more easily penetrate the surface. However, it also makes it unsafe for human consumption as it may contain pollutants or toxins.

The pressure in a fluid increases with depth. This is because the weight of the fluid above exerts a force on the fluid below, causing an increase in pressure. The deeper the fluid, the greater the weight of the fluid above, resulting in a higher pressure at greater depths.

The correct answer is "Weight of a body varies but its mass does not." This statement accurately describes the difference between mass and weight. Mass is a measure of the amount of matter in an object and remains constant regardless of its location. Weight, on the other hand, is the force exerted on an object due to gravity and can vary depending on the strength of the gravitational field. Therefore, an object's weight can change if it is taken to a different location with a different gravitational pull, while its mass will remain the same.

Adhesion refers to the force of attraction between molecules of different substances. It is the ability of a substance to stick to other substances. This force allows molecules of different substances to cling together, such as water sticking to the surface of a glass. Cohesion, on the other hand, refers to the force of attraction between molecules of the same substance. Tension refers to the state of being stretched or strained. Viscosity refers to the resistance of a fluid to flow.