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labwork [276]
3 years ago
6

A ball is dropped from rest and falls to the floor. The initial gravitational potential energy of the ball-Earth-floor system is

10 J. The ball then bounces back up to a height where the gravitational potential energy is 7 J. What was the mechanical energy of the ball-Earth-floor system the instant the ball left the floor?
Physics
1 answer:
Cloud [144]3 years ago
4 0

Answer:

The mechanical energy of the ball-Earth-floor system the instant the ball left the floor is 7 Joules.

Explanation:

It is given that,

Initial gravitational potential energy of the ball-Earth-floor system is 10 J.

The ball then bounces back up to a height where the gravitational potential energy is 7 J.

Let U is the mechanical energy of the ball-Earth-floor system the instant the ball left the floor. Due to the conservation of energy, the mechanical energy is equal to difference between initial gravitational potential energy and the after bouncing back up to a height.

Initial mechanical energy is 10 + 0 = 10 J

Mechanical energy just before the collision is 0 + 10 = 10 J

Final mechanical energy, 7 + 0 = 7 J

Hence, the mechanical energy of the ball-Earth-floor system the instant the ball left the floor is 7 Joules.

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A cannon of mass 6.43 x 103 kg is rigidly bolted to the earth so it can recoil only by a negligible amount. The cannon fires a 7
Nata [24]

Answer:

The velocity of the shell when the cannon is unbolted is 500.14 m/s

Explanation:

Given;

mass of cannon, m₁ = 6430 kg

mass of shell, m₂ = 73.8-kg

initial velocity of the shell, u₂ = 503 m/s

Initial kinetic energy of the shell; when the cannon is rigidly bolted to the earth.

K.E = ¹/₂mv²

K.E = ¹/₂ (73.8)(503)²

K.E = 9336032.1 J

When the cannon is unbolted from the earth, we apply the principle of conservation of linear momentum and kinetic energy

change in initial momentum = change in momentum after

0 = m₁u₁ - m₂u₂

m₁v₁ = m₂v₂

where;

v₁ is the final velocity of cannon

v₂ is the final velocity of shell

v_1 = \frac{m_2v_2}{m_1}

Apply the principle of conservation kinetic energy

K = \frac{1}{2}m_1v_1^2 +  \frac{1}{2}m_2v_2^2\\\\K = \frac{1}{2}m_1(\frac{m_2v_2}{m_1})^2 + \frac{1}{2}m_2v_2^2\\\\K = \frac{1}{2}m_2v_2^2(\frac{m_2}{m_1}) + \frac{1}{2}m_2v_2^2 \\\\K = \frac{1}{2}m_2v_2^2 (\frac{m_2}{m_1} + 1)\\\\2K = m_2v_2^2 (\frac{m_2}{m_1} + 1)\\\\v_2^2 = \frac{2K}{M_2(\frac{m_2}{m_1} + 1)} \\\\v_2^2 = \frac{2*9336032.1}{73.8(\frac{73.8}{6430} + 1)}\\\\

v_2^2 = 250138.173\\\\v_2 = \sqrt{250138.173} \\\\v_2 = 500.14  \ m/s

Therefore, the velocity of the shell when the cannon is unbolted is 500.14 m/s

3 0
3 years ago
What is the difference between 3.15 m and 2.006 m with the correct number of significant figures
snow_lady [41]
The differences is 1.144
5 0
3 years ago
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a pennyfarthing is a style of a bicycle with a very large front wheel and a small real wheel, the cyclist who sit high above and
s344n2d4d5 [400]

Answer:

In one rotation, the large wheel turns 4m.

Explanation:

The given values are:

Input distance,

= 0.64 m

Mechanical advantage,

= 0.16

As we know,

⇒ Out. \ Distance = \frac{Inp. \ distance}{Mechanical \ advantage}

On putting the values, we get

⇒                         =\frac{0.64}{0.16}

⇒                         =4 \ m

4 0
3 years ago
The highest waterfall in the world is the Salto Angel in Venezuela. Its longest single falls has a height of 807 m. If water at
valentina_108 [34]

Answer:

Temperature at the bottom will be 19.18°C

Explanation:

We have given height h = 807 m

Temperature at the top =17.3^{\circ}C

Specific heat of water c = 4200 J/kg/^{\circ}C

From energy conservation

Kinetic energy at the bottom = potential energy at the top

So mc\Delta T=mgh

\Delta T=\frac{gh}{c}=\frac{9.8\times 807}{4200}=1.88^{\circ}C

So temperature at the bottom = 17.3+1.88 = 19.18°C

   

5 0
3 years ago
Why does fluid pressure exist?
zubka84 [21]

Answer:

Fluid pressure from gravity is the weight of the fluid above divided by the area it is pushing on. Fluid pressure applies in all directions. Internal pressure of an object equals the external fluid pressure, otherwise the object could be crushed. Wind and heating can also create pressure.

Explanation:

4 0
3 years ago
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