Exam 12: Equilibrium and Elasticity

A uniform ladder is 10 m long and weighs 400 N.It rests with its upper end against a frictionless vertical wall.Its lower end rests on the ground and is prevented from slipping by a peg driven into the ground.The ladder makes a 30 ° angle with the horizontal.The force exerted on the wall by the ladder is:

A 240-N weight is hung from two ropes as shown.The tension in the horizontal rope has magnitude:

Stress can be measured in:

The center of gravity coincides with the center of mass:

An 800-N man stands halfway up a 5.0 m ladder of negligible weight.The base of the ladder is 3.0 m from the wall as shown.Assuming that the wall-ladder contact is frictionless, the wall pushes against the ladder with a force of:

The ultimate strength of a sample is the stress at which the sample:

A cube with 2.0-cm sides is made of material with a bulk modulus of 4.7 x 10⁵ N/m².When it is subjected to a pressure of 2.0 x 10⁵ Pa the length in cm of its any of its any of its sides is:

If you sit on an ordinary 4-legged chair, which of the following is true?

Strain can be measured in:

A window washer attempts to lean a ladder against a frictionless wall.He finds that the ladder slips on the ground when it is placed at an angle of less than 75 ° to the ground but remains in place when the angle is greater than 75 ° .The coefficient of static friction between the ladder and the ground:

The ideal mechanical advantage (i.e.the ratio of the weight W to the pull P for equilibrium)of the combination of pulleys shown is:

A cube balanced with one edge in contact with a table top and with its center of gravity directly above the edge is in ________ equilibrium with respect to rotation about the edge and in ________ equilibrium with respect to rotation about a horizontal axis that is perpendicular to the edge.

Which of the following is in static equilibrium?

A picture is to be hung from the ceiling by means of two wires.Order the following arrangements of the wires according to the tension in wire B, from least to greatest.

A certain wire stretches 0.90 cm when outward forces with magnitude F are applied to each end.The same forces are applied to a wire of the same material but with three times the diameter and three times the length.The second wire stretches:

A shearing force of 50 N is applied to an aluminum rod with a length of 10 m, a cross-sectional area of 1.0 x 10 ^{x 5} m, and shear modulus of 2.5 x ¹⁰ N/m². As a result the rod is sheared through a distance of:

A picture can be hung on a wall in three different ways, as shown.The tension in the string is:

A cube with edges exactly 2 cm long is made of material with a bulk modulus of 3.5 x 10⁹ N/m².When it is subjected to a pressure of 3.0 x 10⁵ Pa its volume is:

A ladder leans against a wall.If the ladder is not to slip, which one of the following must be true?

A 4.0 m steel beam with a cross sectional area of 1.0 x 10^-2 m² and a Young's modulus of 2.0 x 10¹¹ N/m² is wedged horizontally between two vertical walls.In order to wedge the beam, it is compressed by 0.020 mm.If the coefficient of static friction between the beam and the walls is 0.35, the maximum mass (including its own)it can bear without slipping is: