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Nady [450]
3 years ago
12

A bullet with a mass of 4.5 g is moving with a speed of 300 m/s (with respect to the ground) when it collides with a rod with a

mass of 3 kg and a length of L = 0.25 m. The rod is initially at rest, in a vertical position, and pivots about an axis going through its center of mass which is located exactly halfway along the rod. The bullet imbeds itself in the rod at a distance L/4 from the pivot point. As a result, the bullet-rod system starts rotating together. What is the magnitude of the angular velocity (in rad/s) of the rotation (with respect to the ground) immediately after the collision? You may treat the bullet as a point particle.
Physics
1 answer:
Law Incorporation [45]3 years ago
5 0

Answer:

ω = 5.41 rad/s

Explanation:

Since the rod is rotating around its axis, angular momentum will play part in this question.

The conservation of angular momentum implies that

L_1 = L_2

So, the initial angular momentum is

L_1 = m_b v_b \frac{L}{4} = (4.5\times 10^{-3}~{\rm kg})(300~{\rm m/s})(\frac{0.25}{4}~{\rm m}) = 0.0844~{\rm kg.m^2/s}

The final angular momentum includes the rod and the bullet together. So,

L_2 = I\omega\\I = I_{rod} + I_{bullet} = \frac{1}{12}m_r L^2 + m_b(\frac{L}{4})^2 = \frac{1}{12}3(0.25)^2 + (4.5\times 10^{-3})(\frac{0.25}{4})^2 = 0.0156~{\rm kg.m^2}\\L_2  = L_1 = I\omega\\0.0844 = 0.0156\omega\\\omega = 5.41~{\rm rad/s}

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Tems11 [23]

Answer:

The vibrations from sound waves cause our ears to send signals to our brains to create sound. The speed of sound waves will determine the sound's pitch, or how high or low something sounds. Sound waves are important because they allow us to hear important messages and emergency signals to protect ourselves.

Explanation:

I hope this helps :)

4 0
3 years ago
An electric pump rated 1.5 KW lifts 200kg of water through a vertical height of 6m in 10 secs: way is the efficiency of the pump
ruslelena [56]

Answer:

80%

Explanation:

Efficiency = Power output / Power input × 100 %

To calculate efficiency we need to find power output of electric pump.

We can use,

Work done = Energy change

Work done per second = Energy change per second

Work done per second = Power

Therefore, Power = Energy change per second

                              = Change in potential energy of water per second

                              =mgh / t

                              = 200× 10×6 / 10

                              = 1200 W = 1.2 kW

Now use the first equation to find efficiency,

Efficiency = \frac{1.2}{1.5} × 100%

                = 80 %

8 0
3 years ago
How can global climate change be studied
Marina CMI [18]
Not sure... need help with it 


4 0
3 years ago
Two cars leave towns 680 kilometers apart at the same time and travel toward each other. one car's rate is 10 kilometers per hou
Evgen [1.6K]

D = distance between the cars at the start of time = 680 km

v₁ = speed of one car

v₂ = speed of other car = v₁ - 10

t = time taken to meet = 4 h

distance traveled by one car in time "t" + distance traveled by other car in time "t" = D

v₁ t + v₂ t = D

(v₁ + v₂) t = D

inserting the values

(v₁ + v₁ - 10) (4) = 680

v₁ = 90 km/h

rate of slower car is given as

v₂ = v₁ - 10

v₂ = 90 - 10 = 80 km/h

5 0
3 years ago
Help please physics !!
malfutka [58]

Answer:

Option A. 1 bar = 1 atm

Explanation:

Pressure has various units of measurement. Each unit of measurement can be converted to other units of measurement. For example:

1 atm = 1 bar

1 atm = 760 mmHg

1 atm = 760 torr

1 atm = 1×10⁵ N/m²

1 atm = 1×10⁵ Pa

With the above conversion scale we can convert from one unit to the other.

Considering the question given above, it is evident from the coversion scale illustrated above that only option A is correct.

Thus,

1 bar = 1 atm

5 0
2 years ago
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