Physics - Study Mode
[#256] It is more difficult to walk on a sandy road than on a concrete road because
Correct Answer
(B) the friction between sand and feet is less than that between concrete and feet.
Explanation
Solution: In physics, friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. When walking, the friction between the ground and the feet is crucial for maintaining stability and propulsion. Option A: While it's true that sand is soft and concrete is hard, the question is specifically asking about the difficulty of walking on each surface, which relates more to friction than hardness. Option B: Sand has a lower coefficient of friction compared to concrete. This means that there is less resistance between the feet and the sand, making it more difficult to walk on a sandy road as compared to a concrete road where the friction between the feet and concrete is greater, providing better traction and stability. Option C: This is the opposite of the correct explanation. If the friction between sand and feet were more than that between concrete and feet, walking on sand would be easier, not more difficult. Option D: The texture of the surfaces (grainy sand versus smooth concrete) might play a role in perception, but the primary factor affecting difficulty in walking is the friction between the surfaces and the feet, as explained in option B. Therefore, the correct answer is Option B: the friction between sand and feet is less than that between concrete and feet.
[#257] Find the maximum velocity for the overturn of a car moving on a circular track of radius 100 m. The co-efficient of friction between the road and tyre is 0.2
Correct Answer
(D) 14 m/s
Explanation
Solution: 14 m/s.
[#258] Of the following properties of a wave, the one that is independent of the other is its
Correct Answer
(A) amplitude
Explanation
Solution: The amplitude (A) is independent of other means it is not related to the other quantities.
[#259] On a rainy day, small oil films on water show brilliant colours. This is due to
Correct Answer
(B) interference
Explanation
Solution: On a rainy day, small oil films on water show brilliant colours. This is due to Interference. Interference is a phenomenon in which two waves superimpose to form a resultant wave of greater, lower or same amplitude.
[#260] Point A is at a lower electrical potential than point B. An electron between them on the line joining them will
Correct Answer
(B) Move towards B
Explanation
Solution: Since we know that electric currents move from a higher potential or a lower potential. Also, electrons move in the direction opposite to electric current. So the electron on the line joining two points A and B will move from lower to higher potential i.e, it will move towards B.