What is lenses and types of lenses​

Aman tries to push a box of mass 4 kg with a force of 5 n but the box remains stationary if the coefficient of static friction is 0.45, what is the value of the maximum force of friction?

Phase changes are chemical changes. true or false

How does the amount of energy required to hold each proton and neutron in the nucleus compare to the energy released when they are removed?