The question asks for the scientific term for a push or pull on an object. We need to recall the fundamental definitions of basic physics concepts.
Correct Option: A) Force is defined as a push or a pull upon an object resulting from the object's interaction with another object. It is a vector quantity, meaning it has both magnitude and direction.
The question asks why ball bearings are used in devices like bicycles and cars. This relates to the principle of reducing friction to facilitate smooth movement. We need to understand how ball bearings achieve this.
C) the effective area of contact between the wheel and axle is reduced. Ball bearings achieve their purpose by converting sliding friction into rolling friction, which is much lower. This conversion is facilitated by the small, spherical balls that roll between the moving parts, thereby reducing the effective contact area and making movement smoother and more efficient.
The question asks us to identify the correct statements regarding forces and their effects on objects. We need to evaluate each statement based on the principles of physics related to forces.
Based on the evaluation, statements (ii) and (iii) are correct.
Correct Option: D) (ii) and (iii)
The question asks how the strength of a force is typically expressed. We need to recall the fundamental properties used to describe a vector quantity like force.
B) Magnitude — The strength of a force is indeed expressed by its magnitude. Magnitude gives the numerical value or size of the force, such as 10 Newtons, 50 pounds, etc. Without magnitude, the "strength" of the force cannot be quantified.
The question asks to identify the type of force that friction represents. We need to understand the definitions of different types of forces, specifically distinguishing between contact and non-contact forces.
Correct Option: A) Contact force. Friction is a force that acts when two surfaces are in direct physical contact and opposes their relative motion or tendency of motion.
The question asks to identify the nature of gravity. This is a fundamental concept in physics, specifically classical mechanics and general relativity. We need to recall the basic properties of the gravitational force.
Correct Option: A) Attractive force — Gravity is inherently an attractive force. It always pulls objects with mass towards each other, never pushing them apart.