Which of the following statements is correct for an object moving with constant speed?
A. It may have acceleration
B. Its velocity is constant
C. It must have zero acceleration
D. Its displacement equals distance
Answer: Option A
Solution (By JKSSB Mock Tests)
Constant speed does not imply zero acceleration if direction changes, e.g., uniform circular motion has centripetal acceleration. Velocity may change direction. Displacement magnitude ≤ distance. So only option B is correct.
Explanation:
Thermal radiation is the transfer of heat via electromagnetic waves (primarily infrared). Unlike conduction (which requires physical contact) or convection (which requires fluid movement), radiation can travel through a vacuum. This is how the heat from the Sun reaches the Earth through the vacuum of space.
Explanation:
Range R = u²sin(2θ)/g. sin(2θ) maximum (=1) when 2θ=90° ⇒ θ=45°. Standard result for level ground projection. Memory aid: 'Max range at 45°; max height at 90°'. Projectile motion fact frequently tested in competitive exams.
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