Mechanics

Question 1

Conditions for Static Equilibrium

Answer 1

The sum of both the forces and the moments acting on the body must be equal to zero.

Question 2

Kepler’s 1st Law

Answer 2

All planets move in elliptical orbits with the Sun at one focus.

Question 3

Kepler’s 2nd Law

Answer 3

A line joining any planet to the Sun sweeps out equal areas in equal times.

Question 4

Kepler’s 3rd Law

Answer 4

The square of the period of any planet is proportional to the cube of semi-major axis of its orbit.

Question 5

Conservative Force

Answer 5

Is a force with the property that the total work done in moving a particle between two points is independent of the path taken. Equivalently, if a particle travels in a closed loop, the total work done by a conservative force is zero.

Question 6

Newton’s 1st Law

Answer 6

An object at rest stays at rest unless acted on by an external force.

Question 7

Newton’s 2nd Law

Answer 7

F = ma

Question 8

Newton’s 3rd Law

Answer 8

F_BA = - F_AB

Question 9

4 Fundamental Forces

Answer 9

1. Gravitational interaction
2. Electromagnetic interaction
3. Weak interaction
4. Strong nuclear interaction (hadronic force)

Question 10

Mechanical Energy

Answer 10

The sum of the kinetic and potential energies of a system

Question 11

Total Energy of a System

Answer 11

The energy of a system consists of: mechanical energy, thermal energy, chemical energy and other types of energy - such as sound radiation and electromagnetic radiation.

Question 12

Binding Energy

Answer 12

The energy required to separate a bound system into its constituent parts is called its binding energy. The binding energy is dM*c^2

Question 13

Law of Conservation of Momentum

Answer 13

If the net external force acting on a system remains zero, the total momentum of the system is conserved.

Question 14

Impulse

Answer 14

The impulse of a force is the integral of the force over the time interval during which the force acts

Question 15

Elastic Collisions

Answer 15

The sum of the kinetic energies is the same before and after the collision.

Question 16

Perfectly Inelastic Collision

Answer 16

The two objects stick together and move with the velocity of the centre of mass.

Question 17

Parallel-axis Theorem

Answer 17

The moment of inertia about an axis a distance h from a parallel axis through the centre of mass is
I = I_cm + Mh^2

Question 18

Conservation of Angular Momentum

Answer 18

If the net external torque remains zero, the angular momentum of the system is conserved.

Question 19

Couples

Answer 19

A pair of equal and opposite forces constitutes to a couple.

Question 20

Specific Gravity

Answer 20

… of a substance is the ratio of its density to that of another substance - usually water.

Question 21

Pascal’s Principle

Answer 21

Pressure changes applied to a confined fluid are transmitted undiminished to every point in the fluid and to the walls of the container.

Question 22

Archimedes’ Principle

Answer 22

A body wholly or partially submerged in a fluid is buoyed up by a force equal to the weight of the displaced fluid.

Question 23

Venturi Effect

Answer 23

As air, or anther fluid, passes through a constriction its speed increases and it’s pressure drops.