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2 years ago

5

The earth’s orbit is oval in shape . Explain how the magnitude of gravitational force between earth and sun changes as earth mov

es from position P to Q as shown in the figure.

1 answer:

aleksandr82 [10.1K]2 years ago

3 0

Answer:

The gravitational force does change believe it or not, but the explaination for this is because the earths orbit is an oval (or a not circle) the closer it nears its self to the sun. the suns gravitational pull, pulls the earth to it bringing it closer and as it reaches the other side lets call this L when it reaches L it becomes the same gravitational pull reset as P is and another section over the sun lets call this M and when it reaches M its the same pull as Q, you get it now?

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The density of ice is 0.93 g/cm3. what is the volume, in cm3, of a block of ice whose mass is 5.00 kg? remember to select an ans

serious [3.7K]

The Volume of the ice block is 5376.344 cm^3.

The density of a material is define as the mass per unit volume.

Here, the density of ice given is 0.93 g/cm^3

Mass of the ice block given is 5 kg or 5000 g

Now calculate the volume of the ice block

density=mass/volume

0.93=5000/Volume

Volume =5376.344 cm^3

Therefore the volume of ice block is 5376.344 cm^3

7 0

3 years ago

A cord is used to vertically lower an initially stationary block of mass M = 3.6 kg at a constant downward acceleration of g/7.

dalvyx [7]

Answer:

(a) $W_c=127.008 J$

(b) $W_g=148.176 J$

(c) K.E. = 21.168 J

(d) $v=3.4293m.s^{-1}$

Explanation:

Given:

mass of a block, M = 3.6 kg

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

constant downward acceleration, $a_d= \frac{g}{7}$

$\Rightarrow$ That a constant upward acceleration of $\frac{6g}{7}$ is applied in the presence of gravity.

∴ $a=- \frac{6g}{7}$

height through which the block falls, d = 4.2 m

(a)

Force by the cord on the block,

$F_c= M\times a$

$F_c=3.6\times (-6)\times\frac{9.8}{7}$

$F_c=-30.24 N$

∴Work by the cord on the block,

$W_c= F_c\times d$

$W_c= -30.24\times 4.2$

We take -ve sign because the direction of force and the displacement are opposite to each other.

$W_c=-127.008 J$

(b)

Force on the block due to gravity:

$F_g= M.g$

∵the gravity is naturally a constant and we cannot change it

$F_g=3.6\times 9.8$

$F_g=35.28 N$

∴Work by the gravity on the block,

$W_g=F_g\times d$

$W_g=35.28\times 4.2$

$W_g=148.176 J$

(c)

Kinetic energy of the block will be equal to the net work done i.e. sum of the two works.

mathematically:

$K.E.= W_g+W_c$

$K.E.=148.176-127.008$

K.E. = 21.168 J

(d)

From the equation of motion:

$v^2=u^2+2a_d\times d$

putting the respective values:

$v=\sqrt{0^2+2\times \frac{9.8}{7}\times 4.2 }$

$v=3.4293m.s^{-1}$ is the speed when the block has fallen 4.2 meters.

6 0

3 years ago

The city is thinking about starting a program to add a new chemical to the public pool. Before they do, they want to find out if

Kitty [74]

The best and most correct answer among the choices provided by the question is the fourth choice.

The best people for advising is <span>the government agency that regulates these types of chemicals.</span>
I hope my answer has come to your help. God bless and have a nice day ahead!

4 0

3 years ago

Which device conferts electric energy into mechanical energy

Phantasy [73]

An electric motor converts electrical energy into mechanical energy.

What is electric motor?

An electric motor is an electrical machine that converts electrical energy into mechanical energy.

A generator is mechanically identical to an electric motor, but operates with a reversed flow of power

Hence it will convert mechanical energy into electrical energy.

Some applications of electric motor are:

Industrial fans, blowers and pumps, machine tools, household appliances, power tools, vehicles, and disk drives.

Learn more about electric motor :brainly.com/question/15409160

#SPJ1

4 0

1 year ago

A child of mass m is standing at the edge of a carousel. Both the carousel and the child are initially stationary. The carousel

suter [353]

Answer:

the angular velocity of the carousel after the child has started running =

$\frac{2F}{mR} \delta t$

Explanation:

Given that

the mass of the child = m

The radius of the disc = R

moment of inertia I = $\frac{1}{2} mR^2$

change in time = $\delta \ t$

By using the torque around the inertia ; we have:

T = I×∝

where

R×F = I × ∝

R×F = $\frac{1}{2} mR^2$ ∝

F = $\frac{1}{2} mR$ ∝

∝ = $\frac{2F}{mR}$ ( expression for angular angular acceleration)

The first equation of motion of rotating wheel can be expressed as :

$\omega = \omega_0 + \alpha \delta t$

where ;

∝ = $\frac{2F}{mR}$

Then;

$\omega = 0+ \frac{2F}{mR} \delta t$

$\omega = \frac{2F}{mR} \delta t$

∴ the angular velocity of the carousel after the child has started running =

$\frac{2F}{mR} \delta t$

7 0

3 years ago