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tresset_1 [31]
3 years ago
13

A 2 kg ball is moving 3 m/s when it starts rolling up a hill.

Physics
1 answer:
AURORKA [14]3 years ago
6 0

Answer:

the height reached is = 0.458 [m]

Explanation:

We need to make a sketch of the ball and see the location of the reference point where the potential energy is zero. But the kinetic energy will be defined by the following expression:

Ek=\frac{1}{2} *m*v^{2} \\where:Ek= kinetic energy [J]\\m = mass of the ball [kg]\\v = velocity of the ball [m/s]

Replacing the values on the equation we have:

Ek=\frac{1}{2}*(2)*(3^{2} )\\ Ek=9[J]\\

This kinetic energy will be transformed in potential energy in the moment when the ball starts to rolling up. Therefore the maximum height reached by the ball depends of the initial velocity given to the ball.

Ek=Ep\\where\\Ep=potential energy [J]\\Ep=m*g*h\\where\\g=gravity = 9.81[m/s^2]\\h=height reached [m]\\

Now we have:

h=\frac{Ep}{m*g} \\h=\frac{9}{2*9.81} \\\\h=0.45 [m]

In that moment when the ball reach the 0.45 [m] the potencial energy will be maximum and equal to the kinetic energy when the ball has a velocity of 3[m/s]

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Leno4ka [110]

Answer:

time=4s

Explanation:

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Applying logarithm on both sides,

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now subs. \frac{L}{R}=\frac{2}{log2}

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also log4=log2^{2}=2log2

⇒t=2log2\frac{2}{log2}

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Explanation:

Given

Amanda  spent \frac{2}{5} of her time after school doing Home work

And \frac{1}{4} of her remaining  time riding her bike

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Let t be the time after school

therefore Amanda spend \frac{2t}{5} in home work and  \frac{3t}{5} time is left

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therefore \frac{3t}{5}\times \frac{1}{4}=45

thus t=300 min

therefore time  spent on home work is \frac{2}{5}\times 300=120 min

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