Forces

Question 1

What is Newton’s second law of motion?

Answer 1

F = ma
Resultant Force (N) = Mass (kg) x Acceleration (m/s^2)

Acceleration is directly proportional to the resultant force,
The larger the resultant force, the larger the acceleration

Question 2

What is the principle of moments?

Answer 2

When a body is in equilibrium, the sum of the clockwise moments about any point equals the sun of the anti-clockwise moments about the same point

F1 x d1 = F2 x d2

Question 3

How might the principle of moments be demonstrated?

Answer 3

• Suspend and balance a meter Euler at the 50cm mark using thread.
• Adjust the position of the thread so that the ruler does not rotate.
• Hang unequal masses from either side of metre ruler.
• Adjust the position of the masses until the metre ruler is balance once again
• Gravity exerts forces F1 and F2 on the masses.
• Record the results in a table and repeat for other masses and distances

Question 4

What is Hooke’s Law?

Answer 4

F = k x e
Force = spring constant x extension

Extension is proportional to the load, provided that the proportional limit is not exceeded

Question 5

What is meant by the term pressure?

Answer 5

How force is distributed normally over an area

Pressure = Force / Area
P = F / A

Measured in N / m^2 or Pascals (Pa)