Question

when a force of 5N is applied to a spiral spring,it was stretched by 4mm. what would be the extension if the force is increased by 80%​

Answer 1

Answer:

7.2 mm

Explanation:

80% of 5 =( 80/100)×5 = 4N

new force 5+4= 9N

5N PRODUCES EXTENSION OF 4mm

9 N will produce extension x mm

this is a direct ratio

hence 5×x=9×4

              x= 36/5

               x= 7.2 mm

other method

spring constant k =f/x= 5/4=1.25N/mm

new force = 5N +80% of 5=5+4 =9N

AGAIN F=KX

OR X = F/K= 9/1.25 = 7.2 mm