What is newtons first law of motion

A boy throws a ball up into the air with a speed of 8.2 m/s. The ball has a mass of 0.3 kg. How much gravitational potential ene

diamong [38]

We can use the law of conservation of energy to solve the problem.

The total mechanical energy of the system at any moment of the motion is:
$E=U+K = mgh + \frac{1}{2}mv^2$
where U is the potential energy and K the kinetic energy.

At the beginning of the motion, the ball starts from the ground so its altitude is h=0 and therefore its potential energy U is zero. So, the mechanical energy is just kinetic energy:
$E_i = K_i = \frac{1}{2}mv^2 = \frac{1}{2}(0.3 kg)(8.2 m/s)^2=10.09 J$

When the ball reaches the maximum altitude of its flight, it starts to go down again, so its speed at that moment is zero: v=0. So, its kinetic energy at the top is zero. So the total mechanical energy is just potential energy:
$E_f = U_f$
But the mechanical energy must be conserved, Ef=Ei, so we have
$U_f = K_i$
and so, the potential energy at the top of the flight is
$U_f = K_i = 10.09 J$

7 0

3 years ago

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A string of 26 identical Christmas tree lights are connected in series to a 120 V source. The string dissipates 73 W. What is th

spin [16.1K]

To solve this problem we will apply the concepts related to Ohm's law and Electric Power. By Ohm's law we know that resistance is equivalent to,

$R_{eq}= \frac{V}{I}$

Here,

V = Voltage

I = Current

While the power is equivalent to the product between the current and the voltage, thus solving for the current we have,

$P=VI \rightarrow I = \frac{P}{V}$

$I =0.608 A$

Applying Ohm's law

$R_{eq} = \frac{120V}{0.608A}$

$R_{eq} = 197.4\Omega$

Therefore the equivalent resistance of the light string is $197.4\Omega$

6 0

3 years ago

A box weighing 12,000 N is parked on a 36° slope. What will be the component of the weight parallel to the plane that balances f

sweet-ann [11.9K]

Given :

A box weighing 12,000 N is parked on a 36° slope.

To Find :

What will be the component of the weight parallel to the plane that balances friction.

Solution :

The component of that will be parallel to the plane to balance friction is :

$F \ cos ( 90 - 36)^o\\\\F\ ( sin\ 36^o)$

Therefore, component of force to balance friction is F sin 36° .

Hence, this is the required solution.

5 0

2 years ago

Suppose that a car traveling to the west (-x direction) begins to slow down as it approaches a traffic light. Which statement co

dalvyx [7]

Answer:

Its acceleration is positive

Explanation:

As the car is moving in the negative x-direction than after applying brake then there will be a decrease in the acceleration but in the opposite direction.

As decreasing acceleration consider to be negative but the car is moving in negative direction which means increasing acceleration is negative by sign convention but by applying brake acceleration decrease but in opposite direction than it will give positive value of acceleration.

4 0

3 years ago

Which of the following would be a good question that could be scientifically investigated? What is the best advice a parent can

Nesterboy [21]

<span>"Does lack of sunlight affect plant growth?"

This question can be investigated with procedures according to
the Scientific Method, because "lack of sunlight" can be arranged
unambiguously, and "affected plant growth" can be identified
unambiguously.

The other questions involve words or phrases with ambiguous definitions,
that can mean different things to different people, and would be hard to
agree on, like "</span><span>best advice", "sound quality", and "happiness in life".</span>

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3 years ago

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What is newtons first law of motion​

What is newtons first law of motion