A wire of resistance 9 Ω is bent to form an equilateral triangle. The resistance across any two vertices is MCQ with Answer and Explanation

Explanation:
Atomic number Z = number of protons. Defines chemical element. Mass number = protons + neutrons. Isotopes same Z, different neutrons. Isobars same A, different Z.

Explanation:
Time of ascent = u/g = 4 s. Distance in last second (4th) = ½g(1)²? Actually, during last second of upward journey, velocity becomes zero. Distance = ½g(1)² = 5 m. Formula: s = u - g/2 (2n-1) with n=4? Let's compute: s_nth = u - (g/2)(2n-1). For n=4 (4th second), s = 40 - 5×7 = 40 - 35 = 5 m. Yes.

Explanation:
Maximum friction = μN = 0.4×50 = 20 N. Weight = 50 N. Friction < weight, so block will fall. Wait, force 50 N horizontal, weight 5×10=50 N. Frictional force upward max 20 N, weight 50 N down, net downward 30 N, so it slides down. So it falls down. Answer A. Let's correct: option A: Falls down. I'll set A.