Mechanics & Further Mechanics

Question 1

Scalar

Answer 1

A quantity that has magnitude (size) but not direction.

Question 2

Vector

Answer 2

A quantity that has magnitude (size) and direction.

Question 3

Displacement (m)

Answer 3

Distance moved in a stated direction (a vector).

Question 4

Speed (ms-1)

Answer 4

Distance per unit of time (scalar)

Question 5

Instantaneous Speed

Answer 5

The speed at a specific instance in time (scalar).

i.e. Δ (distance) / Δ (time)

The gradient of a displacement/time graph at a specific time.

Question 6

Average Speed

Answer 6

The distance travelled divided by the time taken to travel that distance (scalar).

Question 7

Velocity (ms-1)

Answer 7

A vector determined by the displacement per unit time (vector).

Question 8

Acceleration (ms-2)

Answer 8

A vector determined by the rate of change of velocity.

Question 9

The Newton (N)

Answer 9

One Newton is the Force that causes 1kg to have an acceleration of 1 ms-2.

Question 10

Weight (N)

Answer 10

The gravitational Force on a body (object).

Weight (N) = mass x acceleration due to gravity (9.81 ms-2).

Question 11

Newton’s Law #1

Answer 11

Every body continues in its state of rest or uniform motion in a straight line unless acted on by a resultant external force.

Question 12

Newton’s Law #2

Answer 12

The rate of change of momentum of a body is directly proportional to the applied resultant force and takes place in the direction in which the resultant force acts.

Question 13

Newton’s Law #3

Answer 13

If a body A exerts a force on a body B then body B exerts a force on body A. The two forces are equal, opposite and in the same straight line (and of the same type).

Note: this is two separate bodies being acted on by forces of the same type.

Question 14

Centre of Gravity

Answer 14

The centre of gravity of an object is a point where the entire weight of an object appears to act.

Question 15

Density (kgm-3)

Answer 15

Mass per unit Volume

Question 16

Work Done by a Force (J)

Answer 16

The energy (scalar, measured in Joules) or work of a Force used in moving through a displacement in the direction of the force.

Question 17

The Joule (J)

Answer 17

The work done when a Force of 1N moves 1 metre in the direction of the Force.

Question 18

Energy (J)

Answer 18

Is the stored ability to do work.

Question 19

Conservation of Energy

Answer 19

In a closed system energy may be converted from one form to another but cannot be created or destroyed.

Question 20

Gravitational Potential Energy (J)

Answer 20

The energy stored in an object (the work it can do) due to its position in a gravitational field.

Question 21

Kinetic Energy (J)

Answer 21

The energy stored in an object due to its speed.

Question 22

Power (W)

Answer 22

The rate of doing work.

Question 23

The Watt (W)

Answer 23

1 Watt is defined as 1 Joule per second.