Exam 11: Static Equilibrium

A 55-kg diver stands at the far end of a 3.0-m long diving board,which has a mass of 32 kg.The diving board is supported at two places,with the first support at the end opposite the diver and the second support 65 cm away from that end.What is the direction and magnitude of the force that the second support applies to the diving board?

A system is in an unstable equilibrium if

Your precocious,22-kg,six year old sister sits asks you to give her an amplitude of 32 degrees for her swing path.In order to do this precisely,you pull her back so that the angle with the vertical that the swing chains make is 32 degrees,and then you let go.As you held her at 32 degrees,what is the tension force in each of the two the swing chains?

A 25-kg uniform ladder 8.0 m long is leaning against a frictionless wall at an angle of 75 degrees above the horizontal.A 40-kg boy climbs 6.0 m up the ladder.What is the magnitude of the frictional force exerted on the ladder by the floor?

A thin 2-dimensional object with uniform mass density is in the shape of a square and has a mass of 2 kg.The sides of the square are 20 cm long each.The coordinate system is drawn with the origin at the center of the square.A point mass,m,of 200 g is placed at one corner of the square object and the assembly is held in equilibrium by positioning the support S at position (x,y)as shown in the drawing.Find the location of the support.

A construction supervisor of mass M = 80.0 kg is standing on a board of mass m = 30.0 kg.Two sawhorses at a distance L = 4.00 m apart support the board.If the man stands a distance x₁ = 1.25 m away from sawhorse 1 as shown,what is the force that the board exerts on that sawhorse?

A 343-kg solid granite cube with each side 52 cm long rests on a level floor.What is the magnitude of the force that is applied directly upward on one of the vertical sides of the cube to just start lifting the bottom edge on that side off the floor?

A 12-kg granite slab that is 2.2 m long is leaning against a frictionless vertical wall,with the base of the slab 55 cm away from the wall.What is the force of friction that the floor must exert on the base of the slab to keep it from moving?

One method of determining the location of the center of gravity of a person is to weigh the person as he/she lies on a board of negligible weight supported by two scales.In one example the height of the man is 190 cm;when he lies on the board,the left scale reads 450 N and the right scale reads 390 N.The center of gravity of the man relative to his feet on the right is

A 75-kg box with a height of 90 cm and a width of 30 cm is at rest on a flat board attached to the bed of a pickup truck.The coefficient of static friction between the box and the board is 0.47.What s the maximum acceleration that the pickup truck can have without the box tipping over?

An airplane flies on a level path with an aerobat standing 22 m along one wing away from the central axis of the airplane.If the aileron on the opposite wing has to provide an additional downward force of 770 N at 15 m from the central axis of the airplane body in order to keep the airplane flying on a level path,what is the mass of the aerobat?

A 5000-kg 200-m bridge is supported at both ends by pylons.A 1900-kg truck is 50 m from one end of the bridge.What force does the pylon nearest the truck exert on the bridge?

The 2-dimensional object of art shown in figure is held in display at a museum by support S and rope R.Support S is on the floor and rope R is attached to the ceiling.The coefficient of static friction between the object and support S is 0.5.If the angle, $\theta$ has its maximum value such that the object remains in static equilibrium on the support,what is the magnitude of the tension in the rope? The object's mass is 25 kg and the distances from object's center of mass,CM,to its contact points with the support and the rope are s = 35 cm and r = 55 cm,respectively.

A mobile is constructed from a metal bar and two wooden blocks as shown in the figure.The metal bar has a mass of 2.0 kg and is 12 cm long.There is a 3.0-kg wooden block hanging from the left end of the metal bar and a string to support the mobile is tied to the metal bar at a distance of 3 cm from the left end.How large of a wooden block should be hung from the right end of the bar to keep the bar level?

A track is built whose height as a function of horizontal position x is given by (h and x,both in meters).If a marble is placed on this track,find the position closest to the axis where it will be in equilibrium.

An object is in static equilibrium.It's then moved a short distance to the right and released.If the equilibrium is neutral,then what will happen next?

Which of the following arrangements of three masses (hanging off the horizontal rod)would result in a balanced mobile?

A 5.00-m long uniform ladder leans against a smooth wall and its base rests on a rough floor.The ladder has a mass of 18.0 kg and its base is a distance of 2.30 m from the wall.A person of mass 70.0 kg climbs 2.50 m up the ladder.Assuming the ladder is to remain in place,what is the magnitude of the force exerted on the ladder by the wall?

A 20-kg child sits on a see saw on the playground,3.0 m from the pivot.A 2^nd child is seated on the other side of the pivot and 2.00 m from the pivot.The mass of the second child needed to lift the first child off the ground is

An object is in static equilibrium.It's then moved a short distance to the right and released.If the equilibrium is stable,then what will happen next?