Physics College

A 25.0 kg child slides down a long slide in a playground. She starts from rest at a height h1 of 21.00 m. When she is partway down the slide, at a height h2 of 8.00 m, she is moving at a speed of 7.80 m/s. Calculate the mechanical energy lost due to friction (as heat, etc.).

Answers

Answer 1

Answer:

The mechanical energy lost due to friction is 2,424.5 J

Explanation:

Given;

mass of the child, m = 25 kg

intial velocity of the child, u = 0

final velocity of the child, v = 7.8 m/s

initial position of the child, h₁ = 21 m

final position of the child, h₂ = 8 m

Let the energy lost due to heat = ΔE

ΔE + ΔK.E  + ΔP.E = 0

ΔE  +   ¹/₂m(v² - u²)  +  mg(h₂ - h₁) = 0

ΔE   +   ¹/₂ x 25(7.8² - 0)    +   25 x 9.8(8 - 21) = 0

ΔE   +  760.5 J   - 3185 J =

ΔE   -  2,424.5 J = 0

ΔE = 2,424.5 J

Therefore, the mechanical energy lost due to friction is 2,424.5 J

Related Questions

Describes the relationship between the free energy change, the reaction quotient, and the equilibrium constant.

Answers

Explanation:

Reaction quotient is defined as the ratio of the concentration of the products and reactants of a reaction at any point of time with respect to some unit. It is represented by the symbol Q.

The ratio of the concentration of products and reactants of a reaction in equilibrium with respect to some unit is said to be equilibrium constant expression. It is represented by the symbol K.

The relationship between Gibbs free energy change and reaction quotient of the reaction is:

[tex]\Delta G=\Delta G^o+RT ln Q[/tex]           ......(1)

where,

[tex]\Delta G[/tex] = Gibbs free energy change

[tex]\Delta G^o[/tex] = Standard Gibbs free energy change

R = Gas constant

T = Temperature

At equilibrium, the free energy change of the reaction becomes 0 and standard Gibbs free energy change can be related to the equilibrium constant by the equation:

[tex]\Delta G^o=-RT ln Q[/tex]           ...(2)

The lamp has a resistance of 10 ohms each resistor has a resistance of 10 ohms what is the total resistance of the circuit

Answers

Mark Brainliest please

Answer : if connected series, 20 ohms
And if connected parallel, answer will be less than 20 ohms

When resistors are wired in series, the total circuit resistance increases because each resistor contributes opposition to the circuit's current flow. Therefore if a 10 ohm resistor is placed in series with another 10 ohm resistor, the total resistance contributed by the two resistors is 20 ohms.

Mark pushes his broken car 140 m down the block to his friend's house. He has to exert a 110 N horizontal force to push the car at a constant speed. How much thermal energy is created in the tires and road during this short trip?

Answers

Answer:

Explanation:

This is a work problem...energy is created and used in the form of work.

W = FΔx where W is work, F is the force needed to move the object Δx in meters.

W = 110(140) ∴

W = 15000 J

You are at a furniture store and notice that a Grandfather clock has its time regulated by a physical pendulum that consists of a rod with a movable weight on it. When the weight is moved downward, the pendulum slows down; when it is moved upward, the pendulum swings faster. If the rod has a mass of 1.23 kg and a length of 1.25 m and the weight has a mass of [10] kg, where should the mass be placed to give the pendulum a period of 2.00 seconds

Answers

Answer:

The distance is 1.026 m.

Explanation:

mass of rod, M = 1.23 kg

Length, L = 1.25 m

mass, m = 10 kg

Time period, T = 2 s

Let the distance is d.

The formula of the time period is given by

[tex]T = 2\pi\sqrt\frac{\frac{1}{3}ML^2+md^2}{(M +m)g}\\\\2\times 2 = 4\pi^2\times \frac{\frac{1}{3}\times1.23\times1.25\times 1.25+ 10d^2}{(1.23 + 10)\times9.8}\\\\11.16 = 0.64 + 10d^2\\\\d= 1.026 m[/tex]

What is the Y-component of a vector A, which is of magnitude
16-12 and at a 45° angle to the horizontal?

Answers

Explanation:

the answer is in the image above

The Y-component of a vector A, which is of magnitude 16√2 and at a 45° angle to the horizontal would be 16

What is a vector quantity?

The quantities that contain the magnitude of the quantities along with the direction are known as the vector quantities.

Examples of vector quantities are displacement, velocity acceleration, force, etc.

As given in the problem we have to find out the  Y-component of a vector A, which is of magnitude  16√12  and at a 45° angle to the horizontal,

Y component of the vector A =  16√2 sin45°

                                                =16√2 ×1/√2

                                                =16

Thus, the Y component of vector A would be 16.

To learn more about the vector quantity here, refer to the link;

https://brainly.com/question/15516363

#SPJ2

Which of the following changes would double the force between two charged particles?
A. Doubling the amount of charge on each particle
B. Increasing the distance between the particles by a factor of 2
C. Decreasing the distance between the particles by a factor of 2
D. Doubling the amount of charge on one of the particles

Answers

Answer:

Doubling the amount of charge on one of the particles.

Explanation:

The force between two charges is given by :

[tex]F=\dfrac{kq_1q_2}{r^2}[/tex]

Where

r is the distance between charges

or

[tex]F\propto \dfrac{1}{r^2}[/tex]

On doubling the charge on one of the particle,

F' = 2F

So, the force gets doubled. Hence, the correct option is (d).

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