Basic Physics

Question 1

What are the 6 SI units?

Answer 1

Mass - kg
Length - m
Time - s
Current - A
Temperature - K
Substance Amount - mol

Question 2

How do you check for homogeneity?

Answer 2

Substitute the units into the equation, they should be equal in both sides.

Question 3

What is density?

Answer 3

The density, ρ, of a material can be found using the following equation: ρ= m/v
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Question 4

When is an object stable?

Answer 4

The object is stable if the line from the centre of gravity, C, passes through the base of the block.

Question 5

What are the conditions for equilibrium?

Answer 5

If a body is in equilibrium, then the following two conditions must be satisfied:

• There is no resultant force in any direction
• There is no net moment about any point.

Question 6

What is a moment defined as?

Answer 6

The moment (or torque) of a force about a point is defined as the force × the perpendicular distance from the point to the line of action of the force. M = F * D

Question 7

What are the conditions for equilibrium based on moments?

Answer 7

For a system to be in equilibrium, the sum of the anticlockwise moments about a point is equal to the sum of the clockwise moments about the same point.