materials and moments Flashcards
State Hooke’s law.
The extension of a spring is directly proportional to the applied force, as long as the elastic limit is not exceeded.
Define the Young modulus of a material and state the condition when it applies.
young modulus = stress/strain.
Condition: It applies as long as the elastic limit is not exceeded
Explain what is meant by plastic deformation.
The material is permanently deformed when stress is removed
Define the force constant of a spring.
The force per unit extension
state Newton’s first law.
A body will remain at rest or continue to move with constant velocity unless acted upon by a force
State Newton’s third law.
When one body exerts a force on another, the other body exerts an equal (in magnitude) and opposite (in direction) force on the first body.
State the principle of conservation of linear momentum.
The total momentum of a closed system is constant (conserved), provided no external forces act on the system.
perfectly elastic Collision
A collision in which both kinetic energy and momentum are conserved
A block of paraffin wax is melting at a constant temperature of 52 °C. Use the behaviour of
paraffin molecules to describe and explain the changes to the internal energy of the molecules
of the paraffin wax as it melts.
(4 marks)
No change in KE
because temperature is constant (during melting)
PE of (the molecules) increases (during melting)
The internal energy increases
