Aforce of 10N Causes spring to exend by 20mm find the spring constant of the spring in N/m & the extension of the spring when 25N is applied &the force applied that Causes an extension of 5mm

Spring constant = 10N/20mm = 0.5N/m

Extension when 25N is applied = 25N/0.5N/m = 50mm

Force applied to cause an extension of 5mm = 5mm x 0.5N/m = 2.5N