A helium-filled balloon, whose envelope has a mass of 0.25 kg, is tied to a 2.0-m-long, 0.050-kg string. The balloon is spherical with a radius of 0.40 m. When released, it lifts a length h of the string and then remains in equilibrium, as in Figure P9.86. Determine the value of h. Hint: Only that part of the string above the floor contributes to the load being supported by the balloon.

A weight of 125 Newton is attached to a brass wire of 7.5 meters long. Young’s modulus for brass is 8.96 X 10^11 Pa. The radius of the wire is 0.7 mm. What is the change in its length in meter?

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On a forest trail a 4m long birch tree trunk is laid across a ravine as a bridge. The trunk is 4m long and just touching each side of the ravine. The trunk is 20cm in diameter and roughly cylindrical. The Young's modulus of birch is 15.2 GPa and its density is 610kg/m. How far does the middle of the trunk bend under its own weight? (answer in mm) Answer:

Please answer correctly. Thanks.

The head of a grass string trimmer has 100 g of cord wound in a light, cylindrical spool with inside diameter 3.00 cm and outside diameter 18.0 cm as shown in the figure below. The cord has a linear density of 10.0 g/m. A single strand of the cord extends 16.0 cm from the outer edge of the spool. 16.0 cm -3.00 cm -18.0 cm- (a) When switched on, the trimmer speeds up from 0 to 2 250 rev/min in 0.230 s. What average power is delivered to the head by the trimmer motor while it is accelerating? Your response differs from the correct answer by more than 10%. Double check your calculations. W

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A 5.00 m -tall, 60.0 cm -diameter concrete column supports a 3.00×105 kg load. By how much is the column compressed?

The normal force of the ground on the foot can reach three times a runner's body weight when the foot strikes the pavement.  By what amount does the 52-cm-long femur of an 75 kg runner compress at this moment? The cross-section area of the bone of the femur can be taken as 5.2×10−4m2 and its Young'’s modulus is 1.6×1010N/m2. Express your answer to two significant figures and include the appropriate units.

An 10.3-kg stone at the end of a steel (Young's modulus 2.0 x 1011 N/m?) wire is being whirled in a circle at a constant tangential speed of 10.0 m/s. The stone is moving on the surface of a frictionless horizontal table. The wire is 4.54 m long and has a radius of 3.56 x 10-3m. Find the strain in the wire.