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3 years ago

6. Gravity formed the planets -True -False

Physics

2 answers:

Sedaia [141]3 years ago

8 0

It’s true because gravity is what pulled the dust and minerals and formed them into plants and dwarf planets.

Studentka2010 [4]3 years ago

6 0

True

Explanation:

When the dust cloud collapsed, it formed a solar nebula—a spinning, swirling disk of material. At the center, gravity pulled more and more material in. Some of them grew big enough for their gravity to shape them into spheres, becoming planets, dwarf planets and large moons.

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Several forces act on a ball. Which of the following statements must be true? The velocity and acceleration could be in any dire

mixer [17]

Answer:

The velocity could be in any direction, but the acceleration is in the direction of the resultant force.

Explanation:

The ball (assuming that we can treat it as a point mass) must obey Newton's 2nd Law, that states that the acceleration produced by a force, is proportional to the applied force, being the mass the proportionality constant.

As the force is the vector, and the mass an scalar, the acceleration vector must be in the same direction as the force vector.

Velocity, instead, can be in any direction: When an object is speeding up is in the same direction as the acceleration, while if it is slowing down, it has just the opposite.

5 0

3 years ago

While rowing in a race, John does 132 J of work while pulling the oar 0.800 m.

HACTEHA [7]

Answer:

i got u!!! john's arms exert a force of 165 newtons.

6 0

3 years ago

Read 2 more answers

Two kids are playing on a newly installed slide, which is 3 m long. John, whose mass is 30 kg, slides down into William (20 kg),

yuradex [85]

Answer:

$v=3.564\ m.s^{-1}$

$\Delta v =2.16\ m.s^{-1}$

Explanation:

Given:

mass of John, $m_J=30\ kg$

mass of William, $m_W=30\ kg$

length of slide, $l=3\ m$

(A)

height between John and William, $h=1.8\ m$

Using the equation of motion:

$v_J^2=u_J^2+2 (g.sin\theta).l$

where:

v_J = final velocity of John at the end of the slide

u_J = initial velocity of John at the top of the slide = 0

Now putting respective :

$v_J^2=0^2+2\times (9.8\times \frac{1.8}{3})\times 3$

$v_J=5.94\ m.s^{-1}$

Now using the law of conservation of momentum at the bottom of the slide:

Sum of initial momentum of kids before & after collision must be equal.

$m_J.v_J+m_w.v_w=(m_J+m_w).v$

where: v = velocity with which they move together after collision

$30\times 5.94+0=(30+20)v$

$v=3.564\ m.s^{-1}$ is the velocity with which they leave the slide.

(B)

frictional force due to mud, $f=105\ N$

Now we find the force along the slide due to the body weight:

$F=m_J.g.sin\theta$

$F=30\times 9.8\times \frac{1.8}{3}$

$F=176.4\ N$

Hence the net force along the slide:

$F_R=71.4\ N$

Now the acceleration of John:

$a_j=\frac{F_R}{m_J}$

$a_j=\frac{71.4}{30}$

$a_j=2.38\ m.s^{-2}$

Now the new velocity:

$v_J_n^2=u_J^2+2.(a_j).l$

$v_J_n^2=0^2+2\times 2.38\times 3$

$v_J_n=3.78\ m.s^{-1}$

Hence the new velocity is slower by

$\Delta v =(v_J-v_J_n)$

$\Delta v =5.94-3.78= 2.16\ m.s^{-1}$

8 0

3 years ago

What do you mean by velocity ratio of a wheel and axle

IgorC [24]

Answer:

Explanation:

In wheel and axle. …with the system is the velocity ratio, or the ratio of the velocity (VF) with which the operator pulls the rope at F to the velocity at which the weight W is raised (VW). This ratio is equal to twice the radius of the large drum divided by the difference…

5 0

3 years ago

An electrician wraps rubber electrical tape around a copper wire. Since rubber is an insulator, which statement best explains th

yuradex [85]

A) Rubber stops charges from flowing. This protects people by stopping electricity from flowing.

Explanation:

The statement that best describes the point of wrapping rubber around the copper wire is that the rubber stops charges from flowing. This prevents people from getting electrical shocks by stopping the flow of electricity.

A rubber is an insulator.
Insulators are substances that prevents the flow of electricity.
The lack free mobile electrons or ions that makes them conductors.
When they are wrapped round a conductor such as copper wire, they will halt the flow of charges.
Copper is a conductor of both heat and electricity. It has free mobile electrons.

learn more:

Metals brainly.com/question/2474874

#learnwithBrainly

4 0

3 years ago