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3 years ago

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A ball of mass 2 kg fallsfrom a rof that is 5 m above the ground. How much gravitational potential energy did the ball lose when

it reached the ground, in units of joules? give your answer as a positive value

1 answer:

Svetllana [295]3 years ago

7 0

Answer:

98.1 J

Explanation:

GPE = mass × g × height

= 2 × 9.81 × 5

= 98.1 J

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A rigid container filled with a gas is placed in ice. What will happen to the pressure of the gas? And what will happen to the v

tankabanditka [31]

The volume of the can remains constant, and as the pressure increases with temperature, the can can't contain the pressure any longer.

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3 years ago

A 15 kg cart is pushed on a frictionless surface from rest horizontally by a 30 N force. What is the cart's acceleration?

Rainbow [258]

Answer:

<em>a. The cart's acceleration is 2 m/s^2</em>

<em>b. The cart will travel 100 m</em>

<em>c. The speed is 20 m/s</em>

Explanation:

a. The acceleration of the cart can be calculated using Newton's second law:

F = m.a

Solving for a:

$\displaystyle a=\frac{F}{m}$

The cart has a mass of m=15 Kg and is applied a net force of F=30 N, thus:

$\displaystyle a=\frac{30}{15}$

$a=2\ m/s^2$

b.

Now we use kinematics to find the distance and speed:

$\displaystyle x = v_o.t+\frac{at^2}{2}$

The cart starts from rest (vo=0). The distance traveled in t=10 seconds is:

$\displaystyle x = 0*10+\frac{2*10^2}{2}$

$x = 100\ m$

The cart will travel 100 m

c.

The final speed is calculated by:

$v_f=0+2*10=20\ m/s$

The speed is 20 m/s

5 0

3 years ago

A cylinder with moment of inertia I1 rotates with angular speed ω0 about a frictionless vertical axle. A second cylinder, with m

MAXImum [283]

Answer:

Part(a): The final angular velocity is $\omega_{f} = \dfrac{I_{1}\omega_{i}}{(I_{1} + I_{2})}$

Part(b): The ratio of the rotational energies is $\dfrac{k_{f}}{k_{i}}& = \dfrac{I_{1}}{(I_{1} + I_{2})}$ ,showing the the energy of th system will decrease.

Explanation:

Part(a):

If ' $I$ ' be the moment of inertia of an object and ' $\omega$ ' be its angular velocity then the angular momentum ' $L$ ' of the object can be written as

$L = I \omega$

If ' $I_{1}$ ' and ' $I_{2}$ ' be the moment of inertia of the two cylinders and ' $\omega_{1}$ ' and ' $\omega_{2}$ ' be the initial angular velocity of the cylinders and ' $\omega_{1}{'}$ ' and ' $\omega_{2}^'}$ ' be their respective final angular velocity, then from conservation of angular momentum,

$I_{1} \omega_{1} + I_{2} \omega_{2} = I_{1} \omega_{1}^{'} + I_{2} \omega_{2}^{'}$

Given, $\omega_{1} = \omega_{i},~\omega_{2} = 0,~\omega_{1}^{'} = \omega_{2}^{'} = \omega_{f}$ . From the above expression

$&& I_{1} \omega_{i} = (I_{1} + I_{2}) \omega_{f}\\&or,& \omega_{f} = \dfrac{I_{1}\omega_{i}}{(I_{1} + I_{2})}$

Part(b):

Initial kinetic energy

$K_{i} = \dfrac{1}{2} I_{1} \omega_{i}^{2}$

and Final kinetic energy

$K_{f} = \dfrac{1}{2}(I_{1} + I_{2}) \omega_{f}^{2}$

Substituting the value of $\omega_{f}$ ,

$&& K_{f} = \dfrac{1}{2}(I_{1} + I_{2})\dfrac{I_{1}^{2}\omega_{i}^{2}}{(I_{1} + I_{2})^{2}} = \dfrac{1}{(I_{1} + I_{2})} \dfrac{1}{2}I_{1}\omega_{i}^{2} = \dfrac{1}{(I_{1} + I_{2})} K_{i}\\&\dfrac{k_{f}}{k_{i}}& = \dfrac{I_{1}}{(I_{1} + I_{2})}$

The above expression shows that the ebergy of the system will decrease.

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3 years ago

Which of the following is a true statement about energy?

Luba_88 [7]

<span>B. Energy is never created nor destroyed.
</span>

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3 years ago

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5. A wave with peaks separated by .34 m has a wavelength of ________________m.

Eduardwww [97]

Answer: 0.17 I think

Explanation:

I asked a doctor

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3 years ago