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iogann1982 [59]
1 year ago
7

In each part calculate the kinetic energy of the given objects in joules a) an automobile whose mass is 1260kg moving at a speed

of 66.3km/h b) a runner whose mass is 64.7 kg, moving at a speed of 8.52m/s c) an electron (mass 9.11x10^31kg) moving at a speed of 2.74x10^7m/s
Physics
1 answer:
Contact [7]1 year ago
5 0

a)

Kinetic energy (KE) = 1/2 m v^2

Where:

m = mass = 1260 kg

v = speed = 66.3 km/h = 18.42 m/s

Replacing:

KE = 1/2 (1260 kg ) (18.42 m/s )^2 = 213,756.7 J

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a kid on a playground swing makes 6 complete to-and-from swings each 30 seconds (a) the frequency of the swinging is? (b) the pe
Mariana [72]

The frequency is how many per second:

       (6 swings)/(30 sec) = (6/30) swing/sec = 0.2 per sec = 0.2 Hz .

The period is how long each one takes, or seconds per swing.
It's exactly the flip of frequency.
So we could just take the frequency, flip it, and find   1 / 0.2 ,
but let's do it the long way:

      (30 sec) / (6 swings) = (30/6) sec/swing =  5 seconds  .  

      
4 0
3 years ago
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A firecracker in a coconut blows the coconut into three pieces. Two pieces of equal mass fly off south and west, perpendicular t
Lisa [10]

Explanation:

Let us assume that piece 1 is m_{1} is facing west side. And, piece 2 is m_{2} facing south side.

Let m_{1} \text{and} m_{2} = m and m_{3} = 2m. Hence,

        2mv_{3y} = m(21)

          v_{3y} = \frac{21}{2}

                     = 10.5 m/s

2mv_{3x} = m(21)

          v_{3x} = \frac{21}{2}

                     = 10.5 m/s

  v_{3} = \sqrt{v^{2}_{3x} + v^{2}_{3y}}

              = \sqrt{(10.5)^{2} + (10.5)^{2}}

              = 14.84 m/s

or,          = 15 m/s

Hence, the speed of the third piece is 15 m/s.

Now, we will find the angle as follows.

          \theta = tan^{-1} (\frac{v_{3y}}{v_{3x}})

                      = tan^{-1}(\frac{10.5}{10.5})

                      = tan^{-1} (45^{o})

                      = 45^{o}

Therefore, the direction of the third piece (degrees north of east) is north of east.

5 0
3 years ago
Cuando el pistón tiene un volumen de 2x10^-4 m^3, el gas en el pistón está a una presión de 150 kPa. El área del pistón es 0.001
Vlad1618 [11]

Answer:

F = 1.128 10⁸ Pa

Explanation:

Pressure is defined by

         P = F / A

If the gas is ideal for equal force eds on all the walls, so on the piston area we have

        F = P A

We reduce the pressure to the SI system

       P = 150 kpa (1000 Pa / 1kPa = 150 103 Pa

we calculate

       F = 150 10³ / 0.00133

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3 0
3 years ago
Suppose you are standing on the edge of a dock and jump straight down. If you land on sand your stopping time is much shorter th
denis-greek [22]

Answer:

In bringing you to a halt, the sand and the water exert the same impulse on you, but the sand exerts a greater average force

Explanation:

7 0
3 years ago
Using the equation zeff=z−s and assuming that core electrons contribute 1.00 and valence electrons contribute 0.00 to the screen
DIA [1.3K]
Thank you for posting your question here at brainly. Below is the solution. I hope the answer will help. 

<span>Cl^- 1s^2 2s^2p^6 3s^2 3p^6 1s^2 2s^2p^6 S = 10; 3s^2 3p^6 S = 0 </span>
<span>Zeff = Z-S = 17- 10 =7 </span>
<span>K^+ 1s^2 2s^2p^6 3s^2 3p^6; 1s^2 2s^2p^6 S = 10; 3s^2 3p^6 S = 0 </span>
<span>Zeff = Z-S = 19- 10 = 9 
</span>
S = 2 + 6.8 + 2.45 = 11.25 
<span>Zeff(Cl^-) = 17 – 11.25 = 5.75 </span>
<span>K^+ 1s^2 2s^2p^6 3s^2 3p^6 same S as for Cl^- but Z increases by 2 hence </span>
<span>Zeff(K^+) = 19 - 11.25 = 7.75</span>
5 0
3 years ago
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