please help ASAP with the following problems

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Conceptual: l] Mechanics sometimes put a length of pipe oyer the handle of a wrench when trying to remove a very tight bolt. How does this help? [It is also hazardous since it can break the bolt.) 2} [a] Suppose you pull a nail at a constant rate using a nail puller. is the nail puller in equilibrium? (b) What ifyou pull the ttail with some acceleration is the ttail puller in equilibrium then? [c] In which case is the force applied to the nail puller larger antl why":l 3] Why are the forces exerted on the outside world by the limbs of our bodies usttally mttch smaller than the forces exerted by muscles inside the body? Textbook: 4] [0.3) Two children push on opposite sides of a door during play. Both push horizontally and perpendicular to the door. One child pushes with a force of 1?.5 N at a distance of 0.500 rn from the hinges, and the second child pushes at a distance of 0.450 m. What force must the second child exert to keep the door from moving? Assume friction is negligible. {23.3 N-m] 5} (0.?) Two children of mass 20 kg and 30 kg sit balanced on a seesaw with the pivot point located at the center of the seesaw. If the children are separated by a distance of 3.0 m, at what distance from the pivot point is the small child sitting in order to maintain the baia nce? (1.0 m) E} (0.1?) To get up on the roof. a person (mass T00 kg} places a b.00-m aluminum ladder [mass 10.0 kg) against the house on a concrete pad with the base of the ladder 2.00 m from the house. The ladder rests against a plastic rain gutter. which we can assume to be frictionless. The center of mass of the ladder is 2.00 m from the bottom. The person is standing 3.00 m from the bottom. 1|ia'Jhat are the forces on the ladder at the top and bottom? (PM, = 133 N away from gutter: Em\"... = T05 N @J 00.4\" above horizontal] T] [9.10111 1?.0-rnhigh and 11.0mteng wall under f ________________ T construction and its bracing are shown in the figure. The Emu wall is in stable equilibrium without the bracing but cart - -------- T 1?.0 m piyet at its base. Calculate the force exerted by each of the - 35".] ll] braces if a strong wind exerts a horizontal felce of (550 N on each square meter of the wall. Assume that the net force from the wind acts at a height halfway tip the wall and that all braces exert equal forces parallel to their 1'0 braces lengths. Neglect the thickness of the wall. [2.12 K 101 hi} 3} [9.21) (a) What is the mechanical advantage of a wheelbarrow, such as the one shown in Figure 9.23, if the center of gravity.i of the wheelbarrow and its load has a perpendicular lever arm of 5.51\".) cm, while the hands have a perpendicular lever arm of 1.02 m? (In) What upward force should you exert to support the wheelbarrow and its load if their combined mass is 55.0 kg? {c} What force does the wheel exert on the ground? (a: 18.5; h: 29.1 N; c: 51D N} 9} (9.32} Even when the head is held erect, as in the figure, its center of mass is not directly over the principal point of support (the atlanto-occipital joint}. The muscles at the hack of the neck should therefore exert a force to keep the head erect. That is whgtr your head falls forward when you fall asleep in the class. (a) Calculate the force exerted by these muscles using the information in the figure. {b} What is the force exerted by the pivot on the head? (a: 25 N downward; h: F5 N upward] to) [9.33) A F'Sikg man stands on his toes by exerting an upward force through ,- the Achilles tendon. as shown. {a} What is the force in the Achilles tendon it he ' stands on one foot? to) CaICulate the force at the pivot of the simplified lever system shownthat force is representative of forces in the ankle joint. (a: 2.2 MI upward: l): 2.9 kN clownwatdj 11] (9.3?) {a} What force should the SUD-kg woman shown exert on the floor with each hand to do a push-up? Assume that she moves up at a constant speed. [b] How much work does she do if her center of mass rises H.240 m? (c) What is her useful power output if she does 25 pushups in one minute? (a: 14'? N downward; h: 118 J; c: 49.0 W)