Question

A 40N force on a spring expands it by 70cm what is the work done on the spring?
A) 1.4 j
B)14 j
C)28 j
D)1.8 j

Answer 1

ANSWER : OPTION C) 28J

EXPLANATION :

Given :

• Force = 40N
• expension of spring = displacement = 70cm

To find : Work done by given force on spring

Formula used :

• W = F.s
• 1m = 100cm

Conversion :

Firstly we need to convert displacement from cm to m { SI unit of displacement }

• 1 m = 100cm
• 1 cm = (1/100)m
• therefore , 70cm = 70/100 m = 0.7m

Solution :

Work done = F.s

Work done = (40)×(0.7)

Work done = 28 J

ANSWER : option C) 28 J

ADDITIONAL INFORMATION :

• Force, displacement & work done are vector quantity, that is depends on direction
• Work is dot product of Force with displacement , that is , W = F.s