The energy stored U in a spring which follows Hooke's Law stretched a distance x from its normal length is U=12 kx2 , where k is the spring constant and basically describes how stretchy a spring is. Which of the following choices correctly writes this a proportionality and identifies the constant of proportionality. Question 4Select one: a. U ∝ x with constant of proportionality 12 kx . b. U ∝ x2 with constant of proportionality 12 k . c. U ∝ 12 with constant of proportionality kx2 . d. U ∝ 12 x with constant of proportionality kx . e. U ∝ 12 k with constant of proportionality x2 .

The tension in a horizontal spring is directly proportional to the extension of the spring. The energy stored in the spring at extension x is E. What is thework done by the spring when its extension changes from x to x/4?A. E/16B. E/4C. 3E/4D. 15E/16

A 25.0 cm tall spring is compressed by 12 mm when a 1.00 kg mass is placed on it.(i) (1 mark)Determine the spring constant of the spring.(ii) (1 mark)Calculate the elastic potential energy stored in the spring.(iii) (1 mark)Where did the energy stored in the spring 'come from'?(iv) (2 marks)The spring is now placed horizontally on a frictionless surface with one end attached to a wall and a 740 g mass attached to the other end. The mass is given a push to set it oscillating. What is the frequency of oscillation?(v) (2 marks)A pendulum is placed above the mass-spring system and the bob oscillates back and forth exactly in time with the mass. How long is the pendulum?

An unstretched spring has a length of 2.0 cm.The spring is then stretched within its limit of proportionality by a tensile force of 1.5 N so that theelastic potential energy stored in the spring is 0.045 J.What is the stretched length of the spring?A 3.0 cm B 5.0 cm C 6.0 cm D 8.0 cm

HOOKE’S LAWthe extension of a spring is in direct proportion withthe load added to it

0 2 . 4 Write down the equation that links extension, force and spring constant.