Which of the following is true?(i) Grooving decreases friction(ii) Streamlining increases friction(iii) Air cushion reduces friction(iv) Ball bearing converts sliding friction into rolling frictionA (ii) and (iii) B (i) and (ii) C (iii) and (iv) D (ii), (iii) and (iv)
Question
Which of the following is true?(i) Grooving decreases friction(ii) Streamlining increases friction(iii) Air cushion reduces friction(iv) Ball bearing converts sliding friction into rolling frictionA (ii) and (iii) B (i) and (ii) C (iii) and (iv) D (ii), (iii) and (iv)
Solution
The correct answer is C (iii) and (iv).
Here's why:
(i) Grooving decreases friction: This is false. Grooving actually increases friction because it increases the surface area for contact.
(ii) Streamlining increases friction: This is also false. Streamlining is a process used to reduce air or fluid resistance (which is a form of friction) on a moving object.
(iii) Air cushion reduces friction: This is true. An air cushion can significantly reduce friction by creating a layer of air between two surfaces, reducing the contact between them.
(iv) Ball bearing converts sliding friction into rolling friction: This is true. Ball bearings are used to reduce friction in the rotation of parts. They work by converting sliding friction into a much smaller amount of rolling friction.
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