Mechanics

Question 1

What is a scalar quantity?

Answer 1

A quantity that has magnitude but no direction.

Question 2

What is a vector quantity?

Answer 2

A quantity that has BOTH magnitude and direction

Question 3

What is equilibrium?

Answer 3

If an object is in equilibrium, all of the forces acting on the object are balanced and cancel each other out.

Question 4

What is a moment?

Answer 4

The turning effect of a force.

Question 5

What is a lever?

Answer 5

Where an effort force is applied to a load force by means of a rigid object rotating around a pivot.

Question 6

What is a couple?

Answer 6

A pair of forces of equal magnitude that act parallel to each other but in opposite directions.

Question 7

What is the centre of mass of an object?

Answer 7

A single point that you can consider the whole weight to act through.

Question 8

How do you find the centre of mass of an object?

Answer 8

1) Hang the object freely from a point.
2) Draw a vertical line downwards from the point of suspension - use a plumb bob to get your line exactly vertical.
3) Hang the object from a different point and draw another line.
4) The centre of mass is where those two lines intersect.

Question 9

What is speed?

Answer 9

How fast something is moving, regardless of direction.

Question 10

What is displacement?

Answer 10

How far an object’s travelled from its starting point in a given direction.

Question 11

What is velocity?

Answer 11

The rate of change of an objects displacement.

Question 12

What is acceleration?

Answer 12

The rate of change in velocity.

Question 13

What does the gradient of a displacement-time graph represent?

Answer 13

Velocity

Question 14

What does the gradient of a velocity-time graph represent?

Answer 14

Acceleration

Question 15

What does the area under a velocity time graph represent?

Answer 15

Displacement

Question 16

What is Newton’s first law?

Answer 16

The velocity of an object will not change unless a resultant force acts on it.

Question 17

What is Newton’s second law?

Answer 17

F = ma

Question 18

What is Newton’s third law?

Answer 18

If an object A exerts a force on object B, then object B exerts an equal but opposite force on object A.

Question 19

What is freefall?

Answer 19

Freefall is where the only force acting on an object is gravity.

Question 20

What is friction?

Answer 20

A force that opposes motion.

Question 21

What is terminal speed?

Answer 21

When the frictional forces acting on an object is equal to the driving force.

Question 22

What is lift?

Answer 22

An upwards force on an object moving through a fluid.

Question 23

What is momentum?

Answer 23

The product of mass and velocity.

Question 24

What is the principle of moments?

Answer 24

The sum of the clockwise moments is equal and opposite to the sum of the anti-clockwise moments.

Question 25

What is an elastic collision?

Answer 25

Where momentum and kinetic energy are conserved, no energy is dissipated as heat, sound.

Question 26

What is impulse?

Answer 26

Defined by the product of force and time.

Question 27

What is work done?

Answer 27

Energy transferred.

Question 28

What is power?

Answer 28

The rate of doing work.

Question 29

What does the conservation of energy state?

Answer 29

Energy cannot be created or destroyed. Energy can be transferred from one form to another but a total amount of energy in a closed system will not change.

Question 30

What is an inelastic collision?

Answer 30

Where momentum is conserved but kinetic energy is not conserved. Energy is dissipated as heat and sound.