Answer to Question #58118 in Mechanics | Relativity for Christbeauty

Question

12 A string of natural length L extends to a new length L' under tensile force F. If Hooke’S law applies, the work done in stretching the spring is ------------
1/2FL
1/2FL'
1/2 F(L-L')
F(L-L')

13 The molecules of a liquid are held together by what type of forces?
cohesive forces
adhesive forces
viscosity
surface tension forces

14 Which of these is correct about viscosity?
it increases with increase in temperature
it varies with the relative velocity of the surfaces in contact
it is does not vary from one liquid to another
both viscous force and upthrust act upwards