Mech

Question 1

Elastic

Answer 1

Kinetic energy is conserved

Question 2

Newton’s first law

Answer 2

Every body remains in a state of rest or uniform motion in a straight line, except insofar as it is compelled to change that state by forces impressed on it

Question 3

Newtons second law

Answer 3

The rate of change of momentum of a body is proportional to the force impressed on it and is effective in the direction in which that force is impressed

Question 4

Galilean invariance

Answer 4

All laws of motion are the same in all inertial frames

Question 5

A string with negligible mass means

Answer 5

Tension force has the same magnitude anywhere along the string

Question 6

Inextensible

Answer 6

Does not stretch so things attached to spring move at the same speed or acceleration

Question 7

Ideal string

Answer 7

Negligible mass and inextensible

Question 8

Conservative forces

Answer 8

They conserve the total energy of the particle

Question 9

Newtons third law

Answer 9

An action is always opposed by an equal and opposite reaction; or, the mutual actions of two bodies are always equal and act in opposite directions

Question 10

Rigid bodies

Answer 10

Objects which preserve their shape during motion

Question 11

Chasles theorem

Answer 11

We can always describe the motion of a rigid body in terms of the translational motion of its centre of mass under the action of the total force applied to the body, together with a rotation that takes place about an axis through the centre of mass due to torques associated with the forces

Question 12

For bodies near the surface of the earth the centre of gravity

Answer 12

Is located in the centre of mass