A ball thrown upward returns to thrower after 6 s. Maximum height reached (g=10 m/s²) is
A. 180 m
B. 90 m
C. 45 m
D. 30 m
Answer: Option C
Solution (By JKSSB Mock Tests)
Total time of flight T = 2u/g => u = gT/2 = 10×6/2 = 30 m/s. Max height H = u²/(2g) = 900/20 = 45 m. Alternatively, time to max height = 3 s, H = ½g t² = ½×10×9 = 45 m.
Explanation:
Nichrome (alloy of nickel, chromium) has high resistivity and high melting point, doesn't oxidize easily at high temperature. Copper has low resistivity, not suitable for heating element.
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