Definations

Question 1

What are base units? List base quantity and unit

Answer 1

From which all other units are derived. Length- metre - m Mass - kilogram - kg Time- second-s Current- ampere - A Temperature interval - kelvin - K Amount of substance - mole - mol

Question 2

Derived unit

Answer 2

Can be described in terms of base units

Question 3

For an equation to be valid it must be _______. Define the missing word. Give an example

Answer 3

Homogeneous. Base units on both sides of the equation are equal. Acc= v-u / t m/s^2 = m/s - m/s / s = m/s^2

Question 4

A vector has both _____ & ________ Whereas ________ only has _______.

Answer 4

Magnitude and direction e.g velocity Scalar e.g speed Magnitude

Question 5

Equalbrium

Answer 5

Opposite forces are equal Object does not move

Question 6

Define these linear motion terms and list eqns to link Displacement Speed Velocity Acceleration

Answer 6

1. The distance moved in a particular direction 2. Rate of change of DISTANCE w/ time 3. Rate of change of DISPLACEMENT w/ time 4. Rate of change of VELOCITY w/ time S= D/T in m/s V=U +AT in m/s S=UT + 1/2 AT^2 in m S=1/2 (V+U) T in m V^2=U^2 + 2AS in m/s

Question 7

What is a physical quainty

Answer 7

Anything that can be measured. Described using a number and unit

Question 8

What is a projectile When an object is under free fall it is travelling at _______

Answer 8

1. An object that is freely moving in earths gravity 2. 9.81 m/s^2

Question 9

What is range? Define using words or eqn At what angle does range have a maximum value

Answer 9

The horizontal distance travelled before returning to the ground Horizontal intial velocity x total time of flight 45 degrees

Question 10

Newton’s first law states

Answer 10

If a body is at rest it will remain at rest unless a resultant force acts on it. If the body is moving in a straight line at constant speed it will remain this way unless a resultant force acts on it.

Law of Inertia

Question 11

Newton’s second law states What force opposes motion

Answer 11

• The acceleration of a body is inversely proportional to its mass and directly proportional to the resultant force and takes place in the same direction as the unbalanced force.
• F=MA where m is mass or
• F=MV -MU /T where m is momentum.

Question 12

What is newtons thrid law?

Answer 12

If body A exerts a force on body B body B will exert a force of the same size on A but in the opposite direction.

One is called ACTION the other REACTION

They act on DIFFERENT bodies so they do not cancel out.

Act on same body? not action-reaction

Question 13

Moment

Centre of: mass

gravity

Answer 13

The product of the force and perpendicular distance from the point to the line of action of the force

M=FxD in NM

The point of an object where we take its :

mass to be conc.

weight to act

Question 14

What is a couple?

State the principle of moments

Answer 14

Two forces that act in opposite directions NOT along the same line? Which causes ROTATION. Produces an unbalanced force.

M= One F x D (perdi. seperation of forces)

When an object is in Rotational equilbrium the sum of the clockwise moments equals the sum of the anti clockwise moments about the same point.

Question 15

Define Energy

Answer 15

The stored ability to do work

Question 16

Work done is a constant force as the product of the force and the distance moved in the direction of the force

Write an equation illustrating this defination

Answer 16

W.D = FxS

J or Nm = NxM

Question 17

A moving object has ________

The equation for this is

Answer 17

Kinetic energy

K.E= 1/2 MV^2

J= KgMS^-1

K.E can also be written in terms of work as W.D= Change in K.E

W.D= 1/2MV^2 – 1/2MU^2

Question 18

An Object has gravational potential energy when?

Answer 18

Raised above the ground

change in P.E= MG(Change in)H

J=Kg x MS^-2 x M

Question 19

Define conservation of energy?

Answer 19

Energy cannot be created or destroyed merely changed from on form to another

Question 20

What is power? ( not the electrical sense)

equations?

Answer 20

The rate of doing work.

P= w.d / t

if displacement occurs at a steady rate

p= FV

power is measured in Joules per second

Question 21

Define efficiency and give equation

Answer 21

How good a device is at transforming one energy form to the other in AN INTENDED WAY

Question 22

Define hookes law

give equation

Answer 22

Up to max load ( limit of proportionality) the extension of an elastic material is proportional to the applied load.

F= kx

where k is a constant and x is the extension

Question 23

L.