14.Which of the following is TRUE of a body in equilibrium. I. The sum of the forces in one direction is equal to the sum of the
forces in the opposite direction

II. The sum of the clockwise forces is equal to the sum of the
anticlockwise forces

III. The sum of the clockwise moments is equal to the sum of the anticlockwise moments

a) I only
b) II only
c) I and III only
d) I, II and III

Explanation:

One

All three statements are saying exactly the same thing.

1. one direction forces = opposite direction forces. Note forces have direction. Always remember that forces have direction and you must always say what that direction is.

2. Two is saying the same thing as one. It is just that 2 is more specific about what the direction is. Clockwise is different from anti clockwise.

3. moments are forces and distances. Forces always have direction. Distances sometimes do not. At your level of study, I don't think it does. Later on, you will learn the word displacement which always has direction and that direction must be stated.

Answer D.

15 We are told to answer just 1 or 2 questions from the same student's posting. There are 4 here, so I'm going to give you just brief answers.

You should realize by now that a loaded bus has it's center of gravity raised. The answer is B

16 A is true.

Technically anything to do with turning is a torque.

D is also true.

C is better worded than B. I would pick B as the odd one out.

17

This is rotating so they must be on the same side of the pivot point. The moments add.

20*3 + 10*2 = 60 + 20 = 80  Newton Meters. Notice C has the right numbers associated with it, but the distance is divided into a Newton. Wrong answer.

In this series of questions, moments are defined as Force * Distance.

need to see circuit to get time constant

conservation of mass

mass before something happens = mass afterwards