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Elena L [17]
3 years ago
12

The acceleration of gravity on Earth is approximately 10 m/s2 (more precisely, 9.8 m/s2). If you drop a rock from a tall buildin

g, about how fast will it be falling after 3 seconds?
Physics
1 answer:
Amiraneli [1.4K]3 years ago
4 0

Given Information:  

Acceleration of gravity = g = 9.8 m/s²

Time period = t = 3 seconds

Required Information:

velocity = v = ?

Answer:  

v = 29.4 m/s

Explanation:  

As we know the velocity of an object under free fall assuming that the object was initially at rest is given by

v = -gt

Where minus sign indicates that the object is moving downward

v = -9.8*3

v = -29.4 m/s

Therefore, the rock will be falling at the speed of 29.4 m/s after 3 seconds.

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Find an expression for the minimum frictional coefficient needed to keep a car with speed v on a banked turn of radius R designe
solniwko [45]
"v0" means that there are no friction forces at that speed
<span>mgsinΘ = (mv0²/r)cosΘ → the variable m cancels </span>
<span>sinΘ/cosΘ = tanΘ = v0² / gr 
</span><span>Θ = arctan(v0² / gr) </span>

<span>When v > v0, friction points downslope: </span>
<span>mgsinΘ + µ(mgcosΘ + (mv²/r)sinΘ) = (mv²/r)cosΘ → m cancels: </span>
<span>gsinΘ + µ(gcosΘ + (v²/r)sinΘ) = (v²/r)cosΘ </span>
<span>µ = ((v²/r)cosΘ - gsinΘ) / (gcosΘ + (v²/r)sinΘ) </span>
<span>where Θ is defined above. </span>

<span>When v > v0, friction points upslope: </span>
<span>mgsinΘ - µ(mgcosΘ + (mv²/r)sinΘ) = (mv²/r)cosΘ → m cancels: </span>
<span>gsinΘ - µ(gcosΘ + (v²/r)sinΘ) = (v²/r)cosΘ </span>
<span>µ = (gsinΘ - (v²/r)cosΘ) / (gcosΘ + (v²/r)sinΘ) </span>
<span>where Θ is defined above. </span>
4 0
3 years ago
Arrange the distances between Earth and various celestial objects in order from least to greatest. Use the conversion table to h
Kaylis [27]

distance to the star Betelgeuse: 640 ly

As we know that

1 ly = 63000 AU

also we know that

1AU = 1.5 \times 10^8 km

1 ly = 63000 (1.5 \times 10^8) = 9.45 \times 10^{12} km

So the distance of Betelgeuse = 640 ly

d_1 = 640 \times 9.45 \times 10^{12} = 6.05 \times 10^{15} m

distance to the star VY Canis Majoris: 3.09 × 10^8 AU

d_2 = 3.09\times 10^8 \times 1.5 \times 10^8 km

d_2 = 4.64 \times 10^{16} km

distance to the galaxy Large Magellanic Cloud: 49976 pc

1 pc = 3.262 ly = 3.262 \times 9.45 \times 10^{12} km

1pc = 3.08 \times 10^{13} km

now we have

d_3 = 49976 \times 3.08 \times 10^{13}

d_3 = 1.54 \times 10^{18} km

distance to Neptune at the farthest: 4.7 billion km

d_4 = 4.7 \times 10^9 km

now the order of distance from least to greatest is as following

1. distance to Neptune at the farthest

2. distance of Betelgeuse

3. distance to the star VY Canis Majoris

4. distance to the galaxy Large Magellanic Cloud

6 0
3 years ago
Two identical positive charges are placed near each other. At the point halfway between the two chargesTwo identical positive ch
Nitella [24]

Answer:The electric field is zero and the potential is positive.

Explanation:

Two identical positive charges are separated by a certain distance and midway between charges two identical positive charges are placed near each other.

So the Electric field at midway is zero because the electric field due to both charges add up to give zero electric field.(because they point in opposite direction)

Potential is scalar quantity and charges are positive so they add up to give potential.

7 0
3 years ago
I need help real quick. Please help me!!
dimaraw [331]
<h3><u>Answer;</u></h3>

D) Standing wave

<h3><u>Explanation;</u></h3>
  • Standing wave also called stationary wave  is a wave which oscillates in time but whose peak amplitude profile does not move in space.
  • A standing wave pattern is a vibrational pattern created within a medium when the vibrational frequency of the source causes reflected waves from one end of the medium to interfere with incident waves from the source.
  • Examples of standing waves include the vibration of a violin string and electron orbitals in an atom.
4 0
3 years ago
A toy cannon uses a spring to project a 5.24-g soft rubber ball. The spring is originally compressed by 5.01 cm and has a force
salantis [7]

Answer:

Speed will be equal to 1.40 m/sec

Explanation:

Mass of the rubber ball m = 5.24 kg = 0.00524 kg

Spring is compressed by 5.01 cm

So x = 5.01 cm = 0.0501 m

Spring constant k = 8.08 N/m

Frictional force f = 0.031 N

Distance moved by ball d = 15.8 cm = 0.158 m

Energy gained by spring

KE=\frac{1}{2}kx^2=\frac{1}{2}\times 8.08\times 0.0501^2=0.0101J

Energy lost due to friction

W=Fd=0.031\times 0.158=0.0048J

So remained energy to move the ball = 0.0101 - 0.0048 = 0.0052 J

This energy will be kinetic energy

\frac{1}{2}mv^2=0.0052

\frac{1}{2}\times 0.00524\times v^2=0.0052

v = 1.40 m/sec

7 0
3 years ago
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