A lightweight spring with spring constant k = 225 N/m is attached to a block of mass m1 = 4.50 kg on a frictionless, horizontal table. The blockspring system is initially in the equilibrium configuration. A second block of mass m2 = 3.00 kg is then pushed against the first block, compressing the spring by x = 15.0 cm as in Figure P16.77A. When the force on the second block is removed, the spring pushes both blocks to the right. The block m2 loses contact with the springblock 1 system when the blocks reach the equilibrium configuration of the spring (Fig. P16.77B). a. What is the subsequent speed of block 2? b. Compare the speed of block 1 when it again passes through the equilibrium position with the speed of block 2 found in part (a). 77. (a) The energy of the system initially is entirely potential energy. E0=U0=12kymax2=12(225N/m)(0.150m)2=2.53J At the equilibrium position, the total energy is the total kinetic energy of both blocks: 12(m1+m2)v2=12(4.50kg+3.00kg)v2=(3.75kg)v2=2.53J Therefore, the speed of each block is v=2.53J3.75kg=0.822m/s (b) Once the second block loses contact, the first block is moving at the speed found in part (a) at the equilibrium position. The energy 01 this spring-block 1 system is conserved, so when it returns to the equilibrium position, it will be traveling at the same speed in the opposite direction, or v=0.822m/s. FIGURE P16.77

Use the data in Table P16.59 for a block of mass m = 0.250 kg and assume friction is negligible. a. Write an expression for the force FH exerted by the spring on the block. b. Sketch FH versus t.

A spring 1.50 m long with force constant 475 N/m is hung from the ceiling of an elevator, and a block of mass 10.0 kg is attached to the bottom of the spring. (a) By how much is the spring stretched when the block is slowly lowered to its equilibrium point? (b) If the elevator subsequently accelerates upward at 2.00 m/s2, what is the position of the block, taking the equilibrium position found in part (a) as y = 0 and upwards as the positive y-direction. (c) If the elevator cable snaps during the acceleration, describe the subsequent motion of the block relative to the freely falling elevator. What is the amplitude of its motion?

The steel system consists of rod CD, rod AB and a rigid bar AC. The diameter of rods CD and AB are 16 mm and 18 mm, 2.0 m T respectively. If a force of 30 kN is applied to point E, determine: a) the normal stress in rod AB and DC, b) the horizontal displacement of point E. Est = 200 GPa. 0.6 m E 0.3 m 30 kN B 4.0 m A

What is the spring constant of the human femur under compression of cross-sectional area 0.001 m and length 0.4 m? Y = 9x10° N/m?.

A vertical spring has a force constant of 150 N/m. By how much will the spring be compressed if a mass 1.30 kg is placed on top of it?

A steel rectangular block, a = 2.4cm wide and b =1.2 cm deep, is subjected to an axial tensile load as shown in the figure. Measurements show the block to increase in length by x = 7.11×10−5m (initial length=10cm) and to decrease width by δ z = 0.533×10−5m, when P is 45 kN. Calculate the modulus of elasticity and Poisson's ratio for the material.

A spring 1.50 m long with force constant 471 N/m is hung from the ceiling of an elevator, and a block of mass 14.1 kg is attached to the bottom of the spring. (a) By how much is the spring stretched when the block is slowly lowered to its equilibrium point? (Enter the magnitude only.) 0.29 m (b) If the elevator subsequently accelerates upward at 1.84 m/s2, what is the position of the block, taking the equilibrium position found in part (a) as y = 0 and upwards as the positive y-direction. (Indicate the direction with the sign of your answer.) 0.054 X Your response differs from the correct answer by more than 10%. Double check your calculations. m (c) If the elevator cable snaps during the acceleration, describe the subsequent motion of the block relative to the freely falling elevator. What is the amplitude of its motion? 0.35 m

A 0.500 kg mass is hung from a vertical spring which then stretches by 10.5 cm. (a) What is the spring constant? (b) What is the elongation of the spring if the 0.500 kg mass is replaced by a1.25 kg mass?