In an isometric exercise a person places a hand on a scale and pushes vertically downward, keeping the
forearm horizontal. This is possible because the triceps muscle applies an upward force M
perpendicular to the arm, as the drawing indicates. The forearm weighs 22.0 N and has a center of
gravity as indicated. The scale registers 111 N. Determine the magnitude of M.
A 1220-N uniform beam is attached to a vertical wall at one end and is supported by a cable at the other
end. A 1960-N crate hangs from the far end of the beam. Using the data shown in the drawing, find (a)
the magnitude of the tension in the wire and (b) the magnitude of the horizontal and vertical
components of the force that the wall exerts on the left end of the beam.
The radius of a sphere of lead (B = 4.2 × 1010 N/m2) is 1.000 m on the surface of the earth where the
pressure is 1.01 × 105 N/m2. The sphere is taken by submarine to the deepest part of the ocean to a
depth of 1.10 × 104 m where it is exposed to a pressure is 1.25 × 108 N/m2. What is the volume of the
sphere at the bottom of the ocean?
A plastic box has an initial volume of 3.50 m3. It is then submerged below the surface of a liquid and its
volume decreases to 3.48 m3.
A woman who weighs 5.00 X 102N is leaning against a smooth vertical wall, as the drawing shows. Find
(a) the force (directed perpendicular to the wall) exerted on her shoulders by the wall and the (b)
vertical component of the force exerted on her shoes by the ground.
The maximum compressional stress that a bone can withstand is 1.6 × 108 N/m2 before it breaks. A
thighbone (femur), which is the largest and longest bone in the human body, has a cross sectional area
of 7.7 × 10–4 m2. What is the maximum compressional force that can be applied to the thighbone?
Young's modulus of nylon is 3.7 × 109 N/m2. A force of 6.0 × 105 N is applied to a 1.5-m length of nylon
of cross sectional area 0.25 m2. By what amount does the nylon stretch?
A cube with edges exactly 2 cm long is made of material with a bulk modulus of 3.5 × 109 N/m2. When it
is subjected to a pressure of 3.0 × 105Pa its volume is:
The distance between the front wheels and the back wheels of the professor's car is 4 m. The center of
mass of the car is located 1 m from the front wheels. If the car has a mass of 1020 kg, what are the forces
that the cars two front tires, Ff, and two rear tires, Fr, exert on the street, when the car is standing on a
horizontal surface?
The shear modulus of steel is 8.1 × 1010 N/m2. A steel nail of radius 7.5 × 10–4 m projects 0.040 m
horizontally outward from a wall. A man hangs a wet raincoat of weight 28.5 N from the end of the
nail. Assuming the wall holds its end of the nail, what is the vertical deflection of the other end of the
nail?
