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Anna [14]
3 years ago
9

If a 0.15 kg ball falls and has a KE of 20 J just before striking the ground, from what height did it fall. A. 1.36m B. 3m C. 13

.6m D. 30m
Physics
1 answer:
RUDIKE [14]3 years ago
5 0
According to the conservation of mechanical energy, the kinetic energy just before the ball strikes the ground is equal to the potential energy just before it fell. 

Therefore, we can say KE = PE
We know that PE = m·g·h

Which means KE = m·g·h

We can solve for h:

h = KE / m·g
   = 20 / (0.15 · 9.8) 
   = 13.6m

The correct answer is: the ball has fallen from a height of 13.6m.

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light travels approximately 982,080,000 ft/s, and one year has approximately 32,000,000 seconds. A light year is the distance li
lapo4ka [179]

Answer:

The distance traveled in 1 year is: 3.143*10^{16}ft

Explanation:

Given

s = 982,080,000 ft/s --- speed

t = 32,000,000 s --- time

Required

The distance traveled

This is calculated as:

Speed = \frac{Distance}{Time}

So, we have:

Distance = Speed * Time

This gives:

Distance = 982,080,000 ft/s * 32,000,000 s

Distance = 982,080,000  * 32,000,000ft

Distance = 3.143*10^{16}ft -- approximated

5 0
2 years ago
Light does not pass through some materials. What do you think happens
Hatshy [7]

Answer:

When an electron is hit by a photon of light, it absorbs the quanta of energy the photon was carrying and moves to a higher energy state. One way of thinking about this higher energy state is to imagine that the electron is now moving faster, (it has just been "hit" by a rapidly moving photon)

A photon is a quantum of EM radiation. Its energy is given by E = hf and is related to the frequency f and wavelength λ of the radiation by. E=hf=hcλ(energy of a photon) E = h f = h c λ (energy of a photon) , where E is the energy of a single photon and c is the speed of light.

7 0
1 year ago
Starting from rest, a 2.1x10-4 kg flea springs straight upward. While the flea is pushing off from the ground, the ground exerts
nirvana33 [79]

Answer:

1.327363 m/s

0.00090243 m

Explanation:

u = Initial velocity

v = Final velocity

m = Mass of flea

Energy

E=\frac{1}{2}m(v^2-u^2)\\\Rightarrow 3.7\times 10^{-4}=2.1\times 10^{-4}(v^2-0)\\\Rightarrow v=\sqrt{\frac{3.7\times 10^{-4}}{2.1\times 10^{-4}}}\\\Rightarrow v=1.32736\ m/s

The velocity of the flea when leaving the ground is 1.327363 m/s

W=F\times s\\\Rightarrow s=\frac{W}{F}\\\Rightarrow s=\frac{3.7\times 10^{-4}}{0.41}\\\Rightarrow s=0.00090243\ m

The flea will travel 0.00090243 m upward

8 0
3 years ago
Please help me with this question, especially the angle part. I have solved the initial velocity already. I don't know what to d
Helga [31]
I think you almost got it.

At the top, the velocity only has horizontal component, so v=12 m/s is v_x, which is v*cos(theta), because v_x is constant, so the same when it was launched or now.

With the value of the initial speed (28 m/s, which is the total speed), you can set

v_x = v * cos( theta ) ---> 12 = 28*cos(theta) --> cos(theta)=12/28=3/7

or theta = 64.62 deg, it is D. Think about it. I hope you see it.
5 0
2 years ago
How do convection currents influence plate tectonics
jarptica [38.1K]

Answer and Explanation:

  • Convection happens when particles with a great deal of warmth vitality in a fluid or gas move and replace particles with less warmth vitality.  
  • Lighter (less thick), warm material ascents while heavier (progressively thick) cool material sinks. It is this development that makes course examples known as convection flows in the environment, in water, and in the mantle of Earth.  
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  • Plates at our planet's surface move in view of the extreme warmth in the Earth's center that causes liquid shake in the mantle layer to move.
  • It moves in an example considered a convection cell that structures when warm material ascents, cools, and in the long run sink down. As the chilled material sinks off, it is warmed and rises once more.
5 0
3 years ago
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