ESG360 Final quiz review

ESG360 Final quiz review

Quiz 5&6 will cover

• Chapter 16: Newton's Law (again)

• Chapter 17: Work and Energy method, Impulse-Momentum method

Multiple Choice

This picture represents what?

• The free-body diagram

• The kinetic diagram

Never draw accelerations on FBDs!

These go on a separate diagram. Remember, the ma terms are the effect of the force terms, not forces themselves.

Multiple Choice

If a body has angular acceleration, which of the following is NOT true?

• Forces add to product of mass and acceleration

• Moments add to zero

• Weight is mass times gravity

• Energy is conserved

Moments do not always add to zero!

If there is angular acceleration, then moments add to  $I\alpha$  as well as any effective moments from the KD. 

Multiple Choice

For the KD shown and assuming CCW positive, the sum of moments about the center of gravity G is

•  $I\alpha$  

•  $I\alpha+rma$  

•  $-I\alpha$  

•  $-I\alpha-rma$  

Multiple Choice

For the KD shown and assuming CCW positive, the sum of effective moments about the point of contact C is

•  $I\alpha$  

•  $I\alpha+rma$  

•  $-I\alpha$  

•  $-I\alpha-rma$  

The point about which you sum moments matters!

For the picture shown, the line ma passes through G, so it does NOT create an effective moment about G.

However, it has perpendicular distance from point C, so it DOES create an effective moment about C.

Multiple Choice

 For the KD shown: If the sum of effective moments is given by $4ft\cdot ma_x$ , these are summed about

• Point G

• The rear wheel

• The front wheel 

• Either wheel

•  None of these are correct

Fill in the Blank

If two flies land on the minute hand of a clock, their _____ velocities must be the same.

Multiple Select

Which of these might be a unit of angular velocity? Check all that apply. 

• 1/s

•  $\frac{ft}{s^2}$  

• N

• rpm