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3 years ago

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Anna learned that every magnet has a north and a south end called poles. One day, while she is playing with magnets she notices

that when she puts the north end of a magnet near the south end of another magnet, they pull together. What can Anna conclude from her observation?
A) Opposite poles of magnets repel.
B) Opposite poles of magnets attract.
C) The north pole picks up iron nails.
D) Only the north pole has an attractive force.

2 answers:

alekssr [168]3 years ago

8 0

B i took the benchmark for k12

maria [59]3 years ago

4 0

B) opposite poles of magnets attract

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PLEASE HELP 15 POINTS AND BRAINIEST!!!<br> Reporting fake answers

Zolol [24]

Answer:

(3) The period of the satellite is independent of its mass, an increase in the mass of the satellite will not affect its period around the Earth.

(4) he gravitational force between the Sun and Neptune is 6.75 x 10²⁰ N

Explanation:

(3) The period of a satellite is given as;

$T = 2\pi \sqrt{\frac{r^3}{GM} }$

where;

T is the period of the satellite

M is mass of Earth

r is the radius of the orbit

Thus, the period of the satellite is independent of its mass, an increase in the mass of the satellite will not affect its period around the Earth.

(4)

Given;

mass of the ball, m₁ = 1.99 x 10⁴⁰ kg

mass of Neptune, m₂ = 1.03 x 10²⁶ kg

mass of Sun, m₃ = 1.99 x 10³⁰ kg

distance between the Sun and Neptune, r = 4.5 x 10¹² m

The gravitational force between the Sun and Neptune is calculated as;

$F_g = \frac{Gm_2m_3}{r^2} \\\\F_g = \frac{6.67\times 10^{-11} \times 1.03 \times 10^{26}\times 1.99\times 10^{30}}{(4.5\times 10^{12})^2} \\\\F_g = 6.751 \times 10^{20} \ N$

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3 years ago

Participating in team sports can have a positive effect on all aspects of life. Please select the best answer from the choices p

AveGali [126]

Answer: True

Explanation:

Participating in team sports can lead to the development of healthy fellowship and brotherhood behavior among the participants. It induces team spirit and allows to lead a healthy competition. It can be a good recreational activity which can be used for removing the emotional and physiological stress. Hence, can improve positivity in all aspects of life.

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3 years ago

During combustion, a fuel’s electromagnetic energy is converted into thermal energy.

swat32

True I believe..................

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3 years ago

A small block of mass 20.0 grams is moving to the right on a horizontal frictionless surface with a speed of 0.68 m/s. The block

Usimov [2.4K]

Answer:

a) $v'=-0.227\ m.s^{-1}$

b) $v=1.36\ m.s^{-1}$

Explanation:

Given:

mass of the lighter block, $m'=0.02\kg$

velocity of the lighter block, $u'=0.68\ m.s^{-1}$

mass of the heavier block, $m=0.04\ kg$

velocity of the heavier block, $u=0\ m.s^{-1}$

a)

Using conservation of linear momentum:

$m'.u'+m.u=m'.v'+m.v$

where:

$v'=$ final velocity of the lighter block

$v=$ final velocity of the heavier block

$m'.u'=m'.v'+m.v$

$m'(u'-v')=m.v$ ........................(1)

Since kinetic energy is conserved in elastic collision:

$\frac{1}{2}m'.u'^2=\frac{1}{2}m'.v'^2+\frac{1}{2}m.v^2$

$m'(u'^2-v'^2)=m.v^2$

$m'(u'-v')(u'+v')= m.v^2$

divide the above equation by eq. (1)

$v=u'+v'$ .............................(2)

now we substitute the value of v from eq. (2) in eq. (1)

$m'(u'-v')=m(u'+v')$

$\frac{m'+m}{m'-m} =\frac{u'}{v'}$

$\frac{0.02+0.04}{0.02-0.04} =\frac{0.68}{v'}$

$v'=-0.227\ m.s^{-1}$ (negative sign denotes that the direction is towards left)

b)

now we substitute the value of v' from eq. (2) in eq. (1)

$m'(u'-v+u')=m.v$

$2m'.u'=(m-m')v$

$2\times 0.02\times 0.68=(0.04-0.02)\times v$

$v=1.36\ m.s^{-1}$

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3 years ago

3) Calculate the kinetic energy of a 7 kg mass traveling at a velocity of 4 m/sec.

murzikaleks [220]

$▪▪▪▪▪▪▪▪▪▪▪▪▪ {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪$

Let's solve ~

Given terms :

Mass (m) = 7 kg

velocity (v)= 4 m/s

The formula to find kinetic Energy is ~

$\boxed{ \boxed{ \sf{ \frac{1}{2} m{v}^{2} }}}$

Now, apply the formula according to given situation

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \: \dfrac{1}{2} \times 7 \times ( {4)}^{2}$

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \: \dfrac{1}{2} \times 7 \times 16$

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \:7 \times 8$

${ \qquad{ \sf{ \dashrightarrow}}} \: \: \sf \:56 \: \: joules$

Therefore, the kinetic Energy of the car is 56 joules

4 0

2 years ago

Read 2 more answers