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Morgarella [4.7K]
2 years ago
4

1. A boy is standing on top of a roof that is 4.5 m high. If he throws a 1.4 kg water balloon down with a velocity of 2m/s,

Physics
1 answer:
Harlamova29_29 [7]2 years ago
3 0

Answer:

The magnitude of the final velocity of the water balloon is 84.3 m/s.

Explanation:

To calculate the velocity of the water balloon when it strikes the ground we need to use the next equation:

v_{f}^{2} = v_{0}^{2} - 2gh

Where:

v_{f}: is the final velocity =?

v_{0}: is the initial velocity = 2 m/s

g: is the gravity = 9.81 m/s²

h: is the height = 4.5 m

By entering the above values into equation (1) we have:

v_{f}^{2} = v_{0}^{2} - 2gh = (2 m/s)^{2} - 2*9.81 m/s^{2}*4.5 m = -84.3 m/s

The minus sign is because the direction of the velocity vector is in the negative vertical axis.  

         

Therefore, the magnitude of the final velocity of the water balloon is 84.3 m/s.

I hope it helps you!

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Wood block 1 in (Figure 1), which has a mass of 1.0 kg, is at rest on a wood ramp. The angle of the ramp is 20º above horizontal
Sergeeva-Olga [200]

Answer:

Explanation:

For this problem we use the translational equilibrium condition. Our reference frame for block 1 is one axis parallel to the plane and the other perpendicular to the plane.

X axis

      -Aₓ - f_e +T = 0        (1)

Y axis

      N₁ - W_y = 0              ( 2)

let's use trigonometry for the weight components

      sin θ = Wₓ / W

      cos θ = W_y / W

      Wₓ = W sin θ

      W_y = W cos θ

We write the diagram for the second body.

Note that in the block the positive direction rd upwards, therefore for block 2 the positive direction must be downwards

      W₂ -T = 0                             (3)

we add the equations is 1 and 3

       - W₁ sin θ - μ N₁ + W₂ = 0

from equation 2

       N₁ = W₁ cos θ

       

we substitute

        -W₁ sin θ - μ (W₁ cos θ) + W₂ = 0

W₂ = m₁ g (without ea - very expensive)

This is the smallest value that supports the equilibrium system

7 0
2 years ago
Suppose that a sound source is emitting waves uniformly in all directions. If you move to a point twice as far away from the sou
Helen [10]

Answer:

<em>d. unchanged.</em>

Explanation:

The frequency of a wave is dependent on the speed of the wave and the wavelength of the wave. The frequency is characteristic for a wave, and does not change with distance. This is unlike the amplitude which determines the intensity, which decreases with distance.

In a wave, the velocity of propagation of a wave is the product of its wavelength and its frequency. The speed of sound does not change with distance, except when entering from one medium to another, and we can see from

v = fλ

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where v is the speed of the sound wave

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λ is the wavelength of the sound wave.

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Hot combustion gases enter the nozzle of a turbojet engine at 260 kpa, 747oc, and 80 m/s. the gases exit at a pressure of 85 kpa
Aleksandr-060686 [28]

Hot combustion gases are accelerated in a 92% efficient adiabatic nozzle from low velocity to a specified velocity. The exit velocity and the exit temp are to be determined.

 

 

Given:

 

T1 = 1020 K à h1 = 1068.89 kJ/kg, Pr1 = 123.4

P1 = 260 kPa

T1 = 747 degrees Celsius

V1 = 80 m/s ->nN = 92% -> P2 = 85 kPa

Solution:

From the isentropic relation,

Pr2<span> = (P2 / P1)PR1 = (85 kPa / 260 kPa) (123.4) = 40.34 = h2s = 783.92 kJ/kg</span>

 

There is only one inlet and one exit, and thus, m1 = m2 = m3. We take the nozzle as the system, which is a control volume since mass crosses the boundary.

 

h2a = 1068.89 kJ/kg – (((728.2 m/s)­2 – (80 m/s)2) / 2) (1 kJ/kg / 1000 m2/s2) = 806.95 kJ/kg\

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5 0
2 years ago
Suppose that a freely falling object were somehow equipped with an odometer. Would the readings of distance fallen each second i
maks197457 [2]

Answer:

1  greater distances fallen in successive seconds

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Where the initial velocity is zero or constant and the acceleration is the acceleration of gravity

Y = - ½ g t2 = - ½ 9.8 t2 = -4.9 t2

Let's look for the position for successive times

t (s)      Y (m)

  1          -4.9

  2         -19.6

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The sign indicates that the positive sense is up

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"Energy deficiency, no coal-burning, no-cost mining pollution" is the correct answer.

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4 0
2 years ago
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