Question

1. Review your notes from 02-28 and your calculation of the moment of inertia of the "rigid rotator,"

• two masses, 7 kg each
• attached to a light titanium bar (neglect this weight)
• separation 4.20 m
• rotation axis halfway between the two masses, perpendicular to the bar.

Our calculation of moment of inertia Iwas

I = ∑ left, right ( m r 2 ) = ( 7 k g ) ( 2.10 m ) 2 + ( 7 k g ) ( 2.10 m ) 2 = 61.74 k g m 2

Let's say that the angular speed ω =5.8 s − 1... i.e., in radians/second.

Calculate the spin angular momentum,L , to the nearest 0.01 k g m 2 sof angular momentum. E.g., if your answer is 22.4498 k g m 2 s, then type 22.45 in the answer box.

2. Review your notes from 02-28 and your calculation of the moment of inertia of the "rigid rotator,"

• two masses, 7 kg each
• attached to a light titanium bar (neglect this weight)
• separation 4.20 m
• rotation axis halfway between the two masses, perpendicular to the bar.

Our calculation of moment of inertia Iwas

I = ∑ left, right ( m r 2 ) = ( 7 k g ) ( 2.10 m ) 2 + ( 7 k g ) ( 2.10 m ) 2 = 61.74 k g m 2

Let's say that the angular speed ω =8.2 s − 1... i.e., in radians/second.

Calculate the rotational kinetic energy, K E rot , to the nearest 0.01 J of energy. E.g., if your answer is 38.675 J, then type 38.68 in the answer box.

3. The conservation of momentum illustrates which understanding(s)?

1. The law holds true regardless of the details of an interaction or how it took place.
2. The law describes the property that determines how much an object resists a change in its motion.
3. The law is an expression that describes an observable physical principle that can be observed and measured.
4. It completely applies to free-fall but nowhere else.

4. A pizza slides across the counter, initially at 4 m/sec, but it slows down and stops due to friction force of 0.65 N. The mass of the pizza is 0.550 kg. Nice.
How much distance is needed to slow down this pizza to a stop?

5. The Transformer known as Bumblebee, transformed to a Camaro, is driving out on University at 25 m/s, westward. Suddenly, he is subjected to a Decepticon trick move, which applies a stopping force, f → d e c e p t , to stop Bumblebee and capture him.

The mass of Bumblebee is 1520 kg. The size of the stopping force is f_decept = 2,640 N.

Calculate the stopping time for this interaction between Bumblebee and the enemies of all sentient beings for whom freedom is an unalienable right.

Type in the numeric part of your answer to the nearest 0.01 s of stopping time. E.g., your stopping time is Δt = 20.408 seconds, then type 20.41 in the answer box.

Answer 1

Solution:

1) Ans:358.09 Kgm²/s

Given,

Distance of the mass from the axis

Moment of inertia

angular speed

The spin angular momentum is given by,

  

  

(2)Ans: 2075.70J

Given,

The rotational kinetic energy is given by,