Question

Name: Date: Lab Section 1. Write out two formulas for torque, and label each term. Vector notation is accepted, and will be counted as a different answer from the 2-Dimensional version. (2 points) What are the units of torque? Newton (N) 2. Choose counterclockwise to be positive. The central circle is taken to be the pivot point. Which forces give positive torques? Which give negative torques? (2 points) 3. Put a checkmark in each of the spaces where the quantity is non-zero. The height of the ground is zero. Potential Energy = PE, kinetic Energy = KE, Momentum = M, Energy E. (2 pts) Recall PE = mgh, KE = % mv, Total E = PE+KE, and momentum is mv. For the position indicated by the red arrow, put a check mark or x for values of the falling ball that are NOT zero. The ball is DROPPED from the holder at the top. Otherwise, leave blank. Momentum: Kinetic Energy: . Total Energy: Potential Energy

Answer 1

1)
i) Torque, $\tau$ = $\vec{r}$ x $\vec{F}$
$\vec{F}$ is the linear force, and $\vec{r}$ is the distance measured from the axis of rotation.
ii) $\tau$ = I$\vec{\alpha}$
I is the moment of inertia, and $\vec{\alpha}$ is the angular acceleration.

Unit - Newton-meter, Nm

2)
Forces F1 and F2 give positive torque. Force F3 give negative torque.

3)

When the is falling, it's velocity increases due to acceleration due to gravity. The velocity will be maximum when the ball hit the ground. Since there is a finite velocity, v in the position indicated,
momentum = mv, kinetic energy = 1/2 mv2 and total energy is non-zero.
At the specified position, the height from the ground is h. Hence the potential energy, mgh is non-zero

Momentum x
Kinetic energy x
Total energy x
Potential energy x