According to Newton's third law, action and reaction forces:
A. Are always equal to weight of the body
B. Act only when bodies are in contact
C. Act on different bodies and never cancel each other
D. Act on the same body and cancel each other
Answer: Option C
Solution (By JKSSB Mock Tests)
Newton's third law states: for every action, there is an equal and opposite reaction. These forces act on two different interacting bodies, hence they never cancel each other as they don't act on the same body. They can act at a distance (e.g., gravitational forces) or through contact. Cancellation of forces occurs only when multiple forces act on a single body. This distinction is crucial for free-body diagram analysis. Exam tip: Always identify which body each force acts upon. Misconception about force cancellation is a common trap in competitive exam questions testing Newton's laws.
Explanation:
F = BIL sinθ. Maximum when θ = 90° (sin90°=1), so perpendicular. Parallel (θ=0°) force zero. This is the motor effect, used in electric motor.
Explanation:
Myopia (near-sightedness) occurs when the image is focused in front of the retina. It is corrected using a concave (diverging) lens. Hypermetropia (far-sightedness) is corrected with a convex (converging) lens. Astigmatism is corrected with a cylindrical lens. Presbyopia is usually corrected with bifocal lenses.
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