A 3 kg block is fastened to a vertical string that has a spring constant of 800 N/m. A 1.2 kg block rests on top of the 3 kg block. When the blocks are at rest, how much is the spring compressed from its uncompressed length?

During a circus act, one performer swings upside down hanging from a trapeze while holding another performer, also upside-down, by the calves. The legs (femurs) of the lower performer undergo deformation due to the upward force from the upper performer. If the upward force on the lower performer's legs is 3mg (three times her weight), how much do the bones (the femurs) in her upper legs stretch in meters? You may assume each bone is equivalent to a uniform rod 34 cm long and 1.75 cm in radius and the legs are massless, serving only to transmit the upward force on the torso. Her mass is 62 kg and Young's modulus for tension on bones is 1.6 × 1010 N/m2.  ΔL =

After a fall, a 89 kg rock climber finds himself dangling from the end of a rope that had been 13 m long and 9.7 mm in diameter but has stretched by 3.4 cm. For the rope, calculate (a) the strain, (b) the stress, and (c) the Young's modulus. (a) Number Units (b) Number Units (c) Number Units

The legs of a weight lifter must ultimately support the weights he has lifted. A human tibia (shinbone) has a circular cross section of approximately 3.6 cm outer diameter and 2.5 cm inner diameter. (The hollow portion contains marrow. ) if a 90 kg lifter stands on both legs, what is the heaviest weight he can lift without breaking his legs, assuming that the breaking stress of the bone is 200 MPa?

During a circus act, one performer swings upside down hanging from a trapeze while holding another performer, also upside-down, by the calves. The legs (femurs) of the lower performer undergo deformation due to the upward force from the upper performer. If the upward force on the lower performer's legs is 3mg (three times her weight), how much do the bones (the femurs) in her upper legs stretch in meters? You may assume each bone is equivalent to a uniform rod 34 cm long and 1.75 cm in radius and the legs are massless, serving only to transmit the upward force on the torso. Her mass is 62 kg and Young's modulus for tension on bones is 1.6 × 1010 N/m2.  ΔL =

A 1.2 x 10-³-kg house spider is hanging vertically by a thread that has a Young's modulus of 4.4 x 10⁹ N/m² and a radius of 18 x 10 m. Suppose that a 65-kg person is hanging vertically on an aluminum (Young's modulus 6.9 x 1010 N/m²) wire. What is the radius of the wire that would exhibit the same strain as the spider's thread, when the thread is stressed by the full weight of the spider? Number i Units

A 62kg load is suspended from a steel wire of diameter 2mm and length 10m. By what distance will the wire stretch (in mm)? Young's modulus (Elastic Modulus) for steel is 2.0 × 10¹¹ Pa

Many caterpillars construct cocoons from silk, one of the strongest naturally occurring materials known. Each thread is typically 2.0 µm in diameter, and the silk has a Young's modulus of 4.0 x 10° N/m2. Assuming that there is no appreciable space between the parallel strands, how many strands N would be needed to N = strands make a rope 8.6 m long that would stretch only 1.02 cm when supporting a pair of 85-kg mountain climbers? Again assuming that there is no appreciable space between the parallel strands, what would be the diameter d of the rope? d = cm

A 480 mm long thighbone (femur), which is the largest and longest bone in the human body, has a cross sectional area of 7.7 × 10–4 m2. A safety factor of 4 applies and the maximum compressional stress that a bone can withstand is 1.6 × 108 N/m2 before it breaks. Young’s Modulus (E ) of a bone at room temperature is 15 × 109 Pa. How much will it compress to support a weight of 1.2 × 105 N?

During a tensile strength experiment, a small diameter fibre is elongated by a force of 0.0250 N. The fibre has an initial length of 0.200 m and stretches 4 x 102 m. Determine the diameter of the fibre? The Young's modulus for the material being tested is 7.60 x 1010 Pa.