An object is moving in a circular path with constant speed. Which of the following remains constant? MCQ with Answer and Explanation

An object is moving in a circular path with constant speed. Which of the following remains constant?
A. Acceleration
B. Linear momentum
C. Kinetic energy
D. Velocity
Answer: Option C
Solution (By JKExamLibrary)
Speed constant implies magnitude of velocity constant, so kinetic energy (½mv²) is constant. Velocity changes due to direction change. Acceleration (centripetal) is directed towards centre, changes direction. Linear momentum vector changes. So only kinetic energy remains constant.

This question belongs to: Science Physics

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The dimensions of surface tension are the same as that of:
A. Pressure
B. Viscosity
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Correct Answer: Option C


Explanation:
Surface tension is defined as Force per unit length (F/L). Dimensional formula: [MLT⁻²] / [L] = [MT⁻²]. A spring constant (k) is defined by Hooke's Law as Force per unit extension (F/x), which also has dimensions [MLT⁻²] / [L] = [MT⁻²]. Thus, both share the same dimensional formula.

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Question #2 Report Error
Assertion (A): When ice floats in water, its approximately 1/10th volume remains outside the water. Reason (R): The density of ice is approximately 10% less than the density of water.
A. Both A and R are true and R is the correct explanation of A.
B. A is true but R is false.
C. Both A and R are true but R is NOT the correct explanation of A.
D. A is false but R is true.

Correct Answer: Option A


Explanation:
The density of ice is about 900 kg/m³ (0.9 g/cm³), while pure water is 1000 kg/m³ (1.0 g/cm³). According to the principle of floatation, the fraction of volume submerged is the ratio of densities: ρ_ice / ρ_water = 0.9. This means 90% is submerged, leaving exactly 10% (1/10th) exposed above the surface. Reason R explains Assertion A.

This question belongs to: Science Physics
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A fuse wire should have
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Correct Answer: Option B


Explanation:
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This question belongs to: Science Physics