A spring, which obeys Hooke's law, has an unstretched length of 15 cm.
A load of 30 N is suspended from the spring.
The new length of the spring is 55 cm.
What is the spring constant k k\,k of the spring?
0.55 N/cm0.55\text{ N/cm}0.55 N/cm
0.75 N/cm0.75\text{ N/cm}0.75 N/cm
1.3 N/cm1.3\text{ N/cm}1.3 N/cm
2.0 N/cm2.0\text{ N/cm}2.0 N/cm
245 exam-style questions on CIE IGCSE Physics 1.5 Forces, covering 1.5.1a Forces, resultant force and motion, 1.5.1b Load–extension graphs and the spring constant, 1.5.1c Friction and drag, 1.5.1d Force, mass and acceleration, 1.5.1e Motion in a circular path, 1.5.2a Moment of a force, 1.5.2b Principle of moments and equilibrium, and 1.5.3 Centre of gravity and stability. Each one has a worked solution and a mark scheme showing where the marks go.