Physics Difficult Question Answer By Vinay Verma Ji Manoj Electrician Ji And Ayush Soni 🇮🇳

🔰 Question Here 🔰 13 - The terminal velocity of a person falling in air depends upon the weight and the area of the person facing the fluid. Find the terminal velocity (in meters per second and kilometers per hour) of an 80.0-kg skydiver falling in a headfirst position with a surface area of  0 . 140 m 2 size 12{0 "." "140"" m" rSup { size 8{2} } } {}

🔰 Question Here 🔰 12 - A freight train consists of two  8 . 00 × 10 5 -kg size 12{8 "." "00" times "10" rSup { size 8{5} } "-kg"} {}  engines and 45 cars with average masses of  5 . 50 × 10 5 kg size 12{5 "." "50" times "10" rSup { size 8{5} } " kg"} {} . (a) What force must each engine exert backward on the track to accelerate the train at a rate of  5 . 00 × 10 − 2 m / s 2 size 12{5 "." "00" times "10" rSup { size 8{ - 2} } m/s rSup { size 8{2} } } {}  if the force of friction is  7 . 50 × 10 5 N size 12{7 "." "50" times "10" rSup { size 8{5} } N} {} , assuming the engines exert identical forces? This is not a large frictional force for such a massive system. Rolling friction for trains is small, and consequently trains are very energy-efficient transportation systems. (b) What is the magnitude of the force in the coupling between t

🔰 Question Here 🔰 11 - Calculate the maximum deceleration of a car that is heading down a  6º size 12{6°} {}  slope (one that makes an angle of  6º size 12{6°} {}  with the horizontal) under the following road conditions. You may assume that the weight of the car is evenly distributed on all four tires and that the coefficient of static friction is involved—that is, the tires are not allowed to slip during the deceleration. (Ignore rolling.) Calculate for a car: (a) On dry concrete. (b) On wet concrete. (c) On ice, assuming that  μ s = 0 . 100 size 12{μ rSub { size 8{s} } =0 "." "100"} {} , the same as for shoes on ice.

🔰 Question Here 🔰 10 - If an object is to rest on an incline without slipping, then friction must equal the component of the weight of the object parallel to the incline. This requires greater and greater friction for steeper slopes. Show that the maximum angle of an incline above the horizontal for which an object will not slide down is  θ = tan –1 μ s . You may use the result of the previous problem. Assume that  a = 0  and that static friction has reached its maximum value.

🔰 Question Here 🔰 9 - Show that the acceleration of any object down an incline where friction behaves simply (that is, where  f k = μ k N size 12{f rSub { size 8{k} } =μ rSub { size 8{k} } N} {} ) is  a = g ( sin θ − μ k cos θ ). size 12{a=g \( "sin"θ - μ rSub { size 8{k} } "cos"θ \) } {}  Note that the acceleration is independent of mass and reduces to the expression found in the previous problem when friction becomes negligibly small  ( μ k = 0 )

            🔰 Question Number - 08 🔰 Consider the 65.0-kg ice skater being pushed by two others shown in  Figure 5.19 . (a) Find the direction and magnitude of  F tot size 12{F rSub { size 8{"tot"} } } {} , the total force exerted on her by the others, given that the magnitudes  F 1 size 12{F rSub { size 8{1} } } {}  and  F 2 size 12{F rSub { size 8{2} } } {}  are 26.4 N and 18.6 N, respectively. (b) What is her initial acceleration if she is initially stationary and wearing steel-bladed skates that point in the direction of  F tot size 12{F rSub { size 8{"tot"} } } {} ? (c) What is her acceleration assuming she is already moving in the direction of  F tot size 12{F rSub { size 8{"tot"} } } {} ? (Remember that friction always acts in the direction opposite that of motion or attempted motion between surfaces in contact.)