Chapter 3&4

Question 1

What is momentum?

Answer 1

Momentum (p) is the product of mass and velocity

Question 2

State the Principle of the Conservation of Momentum

Answer 2

The total momentum before an interaction is equal to the total momentum after, provided no resultant force acts on the systems

Question 3

What is force

Answer 3

Force is that which causes an acceleration

Question 4

What is a newton

Answer 4

The amount of force required to cause a body of mass 1kg to accelerate by 1 m/s(-2)

Question 5

What is Newton’s First Law of Motion

Answer 5

A body will remain at rest or travelling at constant velocity unless a resultant external force acts on it.

Question 6

What is Newton’s Second Law of Motion?

Answer 6

The rate of change of momentum (p) (with respect to time) is directly proportional to the applied force (F) and takes place in the direction of that force.

Question 7

What is Newton’s Third Law of Motion?

Answer 7

For every action there is an equal and opposite reaction. Action and reaction never act on the same body

Question 8

What is Newton’s Law of Universal Gravity?

Answer 8

Any two point masses in the Universe attract each other with a force (F) that is directly proportional to the product of their masses (m) and inversely proportional to the square of the distance (d) between them.

Question 9

What is mass?

Answer 9

Mass (m) is a measure of the amount of matter in a body

Question 10

What is weight?

Answer 10

Weight (w) is a force equal to the product of mass and acceleration due to the gravity

Question 11

What is a centre of gravity?

Answer 11

Centre of gravity is the point at which the whole weight of a body appears to act

Question 12

What is friction?

Answer 12

Friction is a force that opposes the motion of a body

Question 13

What is the moment of a force?

Answer 13

The moment (M) of a force is the product of (the magnitude of the) force and perpendicular distance from the axis to the line of action of the force.

Question 14

What is a lever?

Answer 14

A lever is a rigid body that is free to rotate about a fixed axis

Question 15

What is a couple

Answer 15

A couple is a pair of equal and opposite forces whose lines of action do not coincide

Question 16

What is torque?

Answer 16

The torque of a couple is equal to the product of the magnitude of one of the forces and the distance between the two forces.

Question 17

What is density?

Answer 17

Density (roe) is mass per unit volume

Question 18

What is pressure?

Answer 18

Pressure (p) is force per unit area

Question 19

What is buoyancy/upthrust

Answer 19

Buoyancy is the upward force on a body that is wholly or partially immersed in a fluid

Question 20

State Archimedes Principle

Answer 20

When a body is wholly or partially immersed in a fluid, it experiences an upthrust equal to the weight of the fluid displaced.

Question 21

State the Law of Floatation

Answer 21

The weight of a floating body is equal to the weight of the fluid it displaces.

Question 22

State Boyle’s Law

Answer 22

Pressure is inversely proportional to volume for a fixed mass of gas at constant temperatur

Question 23

What is the first condition of equilibrium?

Answer 23

The vector sum of the forces in any direction is zero

Question 24

What is the second condition for equilibrium?

Answer 24

The vector sum of moments about any point is zero