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3 years ago

What is the mass of a rock if a number 12 N unbalanced force acting on it causes the rock to accelerate at 4 m/s^2

1 answer:

6 0

We can use Newton's second law to find out. This says F=ma, where m is the mass we seek:
$F=ma \\ \\ 12N=m(4 \frac{m}{s^2}) \\ \frac{12N}{4 \frac{m}{s^2}} =3kg$

So we see the mass is 3kg

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The nucleus in an iron atom has a radius of about 4.0 10-15 m and contains 26 protons. (a) What is the magnitude of the repulsiv

zhenek [66]

Answer:

The repulsive electrostatic force between two of the protons is 14.4 N.

Explanation:

Given;

distance between the two protons, r = 4 x 10⁻¹⁵ m

charge of a proton, q = + 1.6 x 10⁻¹⁹ C

The repulsive electrostatic force between two of the protons is calculated by applying Coulomb's law;

$F = \frac{k q_1 q_2 }{r^2} \\\\where;\\k \ is \ Coulomb's \ constant = 9\times 10^9 \ Nm^2/C^2 \\\\F = \frac{9\times 10^9 \ (1.6\times 10^{-19})^2}{(4 \times 10^{-15})^2} \\\\F = 14.4 \ N$

Therefore, the repulsive electrostatic force between two of the protons is 14.4 N.

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3 years ago

A cricketer moves his hands backwards when holding a catch

lisov135 [29]

By doing this he increases the time due to which the rate of change momnetemdecreases. that means the ball comes to rest gently and does not hurt the fielder. but, if does not move his hand backwards, then the ball would come to rest in a fraction of second with a high rate of change of momentum. the ball will exert a lot of force on the hands of the fielder which will hurt him.

3 0

3 years ago

How do vibrations cause sound waves

Mariulka [41]

<span>sound waves are a type of wave sometimes called compression waves, vibrations with enough of an amplitude can compress and decompress the air adjacent to the object causing the waves to form.</span>

3 0

4 years ago

Read 2 more answers

Consider a system consisting of the Earth, a vertical spring attached to the Earth, and a mass attached to the other end of the

Liula [17]

Answer:

The external force leads to an increase on gravitational and spring potential energies.

Explanation:

The system consists of a mass, resort and Earth. According to the Principle of Energy Conservation there is a potential energy as a consequence of the interaction between Earth and the mass and spring potential energy because of the spring deformation and, besides, the existence of work due to an external force:

$U_{g,A} + U_{k,A} + W_{ext} = U_{g,B} + U_{k,B}$

$W_{ext} = (U_{g,B}-U_{g,A}) + (U_{k,B}-U_{k,A})$

$F\cdot \Delta r = \frac{G\cdot m\cdot M}{r_{o}-\Delta r} - \frac{G\cdot m \cdot M}{r_{o}} +\frac{1}{2}\cdot k \cdot (x_{o}+\Delta r)^{2} - \frac{1}{2} \cdot k \cdot (x_{o})^{2}$

$F\cdot \Delta r = G\cdot m \cdot M \cdot \left(\frac{1}{r_{o}-\Delta r}-\frac{1}{r_{o}} \right)+\frac{1}{2}\cdot k \cdot [(x_{o}+\Delta r)^{2} -x_{o}^{2}]$

The external force leads to an increase on gravitational and spring potential energies.

7 0

3 years ago

Read 2 more answers

It’s estimated that there are a trillion comets in the Oort cloud, which extends out to about 50,000 AU.How much space does each

dexar [7]

Answer:

Each comet has 523 UA³
The typical spacing would be 8.05 UA
2.0181x10^21 Joules

Explanation:

Assuming comets are evenly distributed we can find first the volume of a sphere with the formula frac{{4}{3}}πr³ using 50000 as the radius, and then dividing this volume by the amount of comets. This gives a the space each comet has on average.
We apply the cube root as proposed in the question.
The kinectic energy is given <em>K=frac{{1}{2}}mv² where m is the mass and v is the velocity. Apropriate unit are given in the question.</em>

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4 years ago