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marusya05 [52]
2 years ago
9

A playground slide is 8.80 ft long and makes an angle of 25.0° with the horizontal. A 63.0-kg child, initially at the top, slide

s all the way down to the bottom of the slide. (a) Choosing the bottom of the slide as the reference configuration, what is the system's potential energy when the child is at the top and at the bottom of the slide? What is the change in potential energy as the child slides from the top to the bottom of the slide? (Include the sign of the value in your answer.)
Physics
1 answer:
mario62 [17]2 years ago
7 0

Answer:

initial: 1654.6 J, final: 0 J, change: -1654.6 J

Explanation:

The length of the slide is

L = 8.80 ft = 2.68 m

So the height of the child when he is at the top of the slide is (with respect to the ground)

h = L sin \theta = (2.68 m)sin 25.0^{\circ}=1.13 m

The potential energy of the child at the top is given by:

U = mgh

where

m = 63.0 kg is the mass of the child

g = 9.8 m/s^2 is the acceleration due to gravity

h = 1.13 m

Substituting,

U=(63.0 kg)(9.8 m/s^2)(2.68 m)=1654.6 J

At the bottom instead, the height is zero:

h = 0

So the potential energy is also zero: U = 0 J.

This means that the change in potential energy as the child slides down is

\Delta U = 0 J - (1654.6 J) = -1654.6 J

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A bowler throws a bowling ball of radius R = 11 cm down the lane with initial speed v₀ = 7.5 m/s. The ball is thrown in such a w
salantis [7]

Answer:

a) t = 0.74s

b) D = 4.76m

c) Vf = 5.35m/s

Explanation:

The ball starts rolling when Vf = ωf*R.

We know that:

Vf = Vo - a*t

ωf = ωo + α*t

With a sum of forces on the ball:

Ff = m*a

\mu*N = m*a

\mu*m*g = m*a

a=\mu*g=2.9m/s^2

With a sum of torque on the ball:

Ff*R = I*\alpha

\mu*m*g*R = 2/5*m*R^2*\alpha

\alpha=5/2*\mu*g/R=65.9rad/s^2

Replacing both accelerations:

Vo - a*t=\alpha*t*R

7.5 - 2.9*t=65.9*t*0.11

t=0.74s

The distance will be:

D = Vo*t-1/2*a*t^2

D = 4.76m

Final velocity:

Vf=Vo-a*t

Vf=5.35m/s

7 0
3 years ago
Una carga de -10Mc está situada a 20cm delante de otra carga de 5 Mc. Calcular la fuerza electrostática en Newton ejercida por u
tino4ka555 [31]

Answer:

a)  force between them is attraction,   b)  F = 1.125 10⁻² N

Explanation:

In this case the electric force is given by Coulomb's law

          F =k \frac{q_1q_2}{r^2}

           

In the exercise they give us the values ​​of the loads

          q1 = - 10 mC = -10 10⁻³ C

          q2 = 5 mC = 5 10⁻³ C

           d = 20 cm = 0.20 m

let's calculate

          F = 9 10⁹ \frac{10 \ 10^{-3} \ 5 \ 10^{-3}}{0.20^2}

          F = 1.125 10⁻² N

To find the direction of the force we use that charges of the same sign repel each other, as in this case there is a positive and a negative charge, the force between them is attraction

7 0
3 years ago
a ultrasonic wave at 8x10^4 Hz is emitted into a vien where the speed of sound in blood is 1570 m/s. the wave reflects off the r
Aneli [31]

Answer: 0.392 m/s

Explanation:

The Doppler shift equation is:

f'=\frac{V+V_{o}}{V-V_{s}} f

Where:

f=8(10)^{4} Hz is the actual frequency of the sound wave

f'=8.002(10)^{4} Hz is the "observed" frequency

V=1570 m/s is the speed of sound

V_{o}=0 m/s is the velocity of the observer, which is stationary

V_{s} is the velocity of the source, which are the red blood cells

Isolating V_{s}:

V_{s}=\frac{V(f'-f)}{f'}

V_{s}=\frac{1570 m/s(8.002(10)^{4} Hz-8(10)^{4} Hz)}{8.002(10)^{4} Hz}

Finally:

V_{s}=0.392 m/s

3 0
2 years ago
The phenomenon of water sticking to a surface, such as a window pane or
Korolek [52]

Answer:

Because of the Cohesion

4 0
1 year ago
Read 2 more answers
Question 24 1 pts Find the voltage in an extension cord having a 0.0600 22 resistance and through which a 5.00A current is flowi
Neporo4naja [7]

The voltage in the extension cord is 30 V.

The problem above can be solved using ohm's law

⇒ Formula:

V = IR.................. Equation 1

⇒ Where:

  • V = Voltage in the extension cord
  • I = Current flowing through the extension cord
  • R = Resistance of the extension cord.

From the question, I think there was a slight error in the value of the current given it suppose to be 500 A, and not 5.00 A

⇒ Given:

  • I = 500 A
  • R = 0.06 ohms

⇒ Substitute these values into equation 1

  • V = 500(0.06)
  • V = 30 V

Hence the voltage in the extension cord is 30 V

Learn more about voltage here: brainly.com/question/4429782

6 0
2 years ago
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