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3 years ago

Which of the following examples does not illustrate Newton's first law of motion?

Physics

1 answer:

Stella [2.4K]3 years ago

6 0

Answer: B

Explanation: The rocket is accelerating the the spacecraft. Accelerating relates to Newtons Second Law of Motion.

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What is the SI unit of electric charge

shusha [124]

Answer:

The SI unit for electric chargeis the C (which is the abbreviation of Coulomb}

Explanation:

The SI unit for electric chargeis the Coulomb. The letter used is the C.

1 C = 1 As

4 0

3 years ago

A soccer ball is kicked from the top of one building with a height of H1 = 30.2 m to another building with a height of H2 = 12.0

viktelen [127]

Hi there!

Initially, we have gravitational potential energy and kinetic energy. If we set the zero-line at H2 (12.0m), then the ball at the second building only has kinetic energy.

We also know there was work done on the ball by air resistance that decreased the ball's total energy.

Let's do a summation using the equations:
$KE = \frac{1}{2}mv^2 \\\\PE = mgh$

Our initial energy consists of both kinetic and potential energy (relative to the final height of the ball)

$E_i = \frac{1}{2}mv_i^2 + mg(H_1 - H_2)$

Our final energy, since we set the zero-line to be at H2, is just kinetic energy.

$E_f = \frac{1}{2}mv_f^2$

And:
$W_A = E_i - E_f$

The work done by air resistance is equal to the difference between the initial energy and the final energy of the soccer ball.

Therefore:
$W_A = \frac{1}{2}mv_i^2 + mg(H_1 - H_2) - \frac{1}{2}mv_f^2$

Solving for the work done by air resistance:
$W_A = \frac{1}{2}(.450)(15.1^2)+ (.450)(9.8)(30.2 - 12) - \frac{1}{2}(.450)(19.89^2)$

$W_A = \boxed{42.552 J}$

8 0

2 years ago

What is the voltage of a computer with 30 Ω of resistance and 15 amps of current?

Kryger [21]

Answer:

120 V

Explanation:

5 0

2 years ago

The orbital radius of an electron in a hydrogen atom is 0.846 nm. What is its de Broglie wavelength?

kotykmax [81]

Answer:

The value is $\lambda = 1.329 *10^{-9} \ m$

Explanation:

From the question we are told that

The orbital radius is $r = 0.846nm = 0.846 *10^{-9} \ m$

Generally the de Broglie wavelength is mathematically represented as

$\lambda = \frac{2 * \pi r}{4}$

substituting values

$\lambda = \frac{ 2 * 3.142 * 0.846 *10^{-9}}{4}$

$\lambda = 1.329 *10^{-9} \ m$

6 0

3 years ago

Calculate the kinetic energy in joules of a 1,500 kg car that is moving at a speed of 42 km/h

Rzqust [24]

Data:
KE (Kinetic Energy) = ? (Joule)
m (mass) = 1500 Kg
v (speed) = 42 Km/h
converting to m/s (42 / 3.6), we have: v (speed) = 11.6 m/s

Formula:
$K_{E} = \frac{1}{2} m*v^2$

Solving:
$K_{E} = \frac{1}{2} m*v^2$
$K_{E} = \frac{1}{2} *1500*(11.6)^2$
$K_{E} = \frac{1}{2} *1500*134.56$
$K_{E} = \frac{201840}{2}$
$\boxed{\boxed{K_{E} = 100920\:Joule}}\end{array}}\qquad\quad\checkmark$

4 0

2 years ago