A ball is thrown vertically upward with velocity 49 m/s. Maximum height (g=9.8) is MCQ with Answer and Explanation

Explanation:
F = G m1 m2 / r² = 6.67×10⁻¹¹ × 6 / 4 = 6.67×10⁻¹¹ × 1.5 = 1.0005×10⁻¹⁰ N.

Explanation:
The area under velocity-time graph gives displacement when direction is considered (signed area), and distance travelled when absolute values are taken (unsigned area). For unidirectional motion, both are equal. Velocity is rate of change of displacement, so integrating velocity over time yields displacement. This graphical interpretation is fundamental in kinematics. Memory tip: Slope of v-t graph = acceleration; area under v-t graph = displacement. Competitive exams often combine graph analysis with conceptual understanding to test depth of knowledge in motion topics.

Explanation:
When light crosses media, frequency remains constant as it's determined by the source. Speed and wavelength change proportionally: v = fλ, and v = c/n, so λ decreases in denser medium (glass). Amplitude may change due to reflection/transmission coefficients. Memory aid: 'Frequency is source-dependent; speed and wavelength are medium-dependent'. This fundamental wave property is frequently tested in refraction questions. Competitive exams often use this to assess understanding of wave behavior at interfaces. Always recall that color (frequency) doesn't change during refraction, though speed and wavelength do.