The orbit of the Earth around the Sun is approximately circular, and takes one year to complete. The Earth's mass is 6×1024kg, and the distance from the Earth to the Sun is 1.5×1011m. What is (dp\/dt)pof the Earth? What is p(dp/dt)of the Earth? What is the magnitude of the gravitational force the Sun (mass 2×1030kg) exerts on the Earth? What is the direction of this force?

Short Answer

Expert verified

The value of d\p\dtp=0and\p\dpd=3.55×1022kg.m/s2and the gravitational force is3.55×1022N and the direction of the force is toward the centre of the path.

Step by step solution

01

Given

The orbit of the Earth around the Sun is approximately circular, and takes one year to complete. The Earth's mass is mE=6×1024kg, and the distance from the Earth to the Sun is R=1.5×1011mand the mass of sun is m2=2×1030kg

02

Definition of force.

A force is a push or pull on an object caused by the interaction of the thing with another object. Every time two things interact, a force is exerted on each of them. The two items no longer feel the force after the interaction ends

03

Determine the (dp→\ /dt)p,p(dp/dt),the magnitude of the gravitational force of the Sun and the direction of this force.

msThe speed is the change in the distance with time.

v=dt

The Earth moves above the circumference of a circle when it completes one round.

The circumference is given bylocalid="1656737485321" 2πR

Where R is the radius of the circle (distance between the wooden horse and the center of the carousel).

So, the distance isd=2πR

Therefore,

v=2πRt

Now plug the values for R and t to get the speed of the wooden horse

t=(1year)(365 day/year) (24hr / day)(3600s/h)

=31.536×106s

Therefore,

v=2πRt=2π1.5×1011m31.536×106s=2.98×103m/s

The net force on an object is equal to the rate of change of momentum and can be written as the sum of two components.

The parallel rate of change of momentum dpdtand the perpendicular rate of change of momentum dpdtare the two elements that we are concerned with.

So, the change of momentum required is given by

dpdt=dpdt+dpdt\

The parallel rate of change of momentum affects the object's speed, and since the speed is constant, the parallel rate is zero and equal to the rate of change of the size of the momentum.

dpdt=dpdtp=0

As a result, the rate change is the direction change owing to the perpendicular rate of change.

The magnitude of the perpendicular rate change equals the rate change of the direction of the momentum and at speeds much less than the speed of light is given by

dpdt=pdpdt=mEv2R

Now put the values for m,v and R) to getpdpdt

pdpdt=mEv2R=6×1024kg2.98×103m/s1.5×1011m=3.55×1022kg.m/s

Also, there is a gravitational force between the Earth and the Sun and it is given by

Fg=GmEmsR2

Where G is the gravitational constant and equals 6.67×10-11N.m2/kg2,mEis the mass of the earth, and is the mass of the Sun.

Now put the values for mE,role="math" localid="1656739496454" ms,G and R to get Fg

Fg=GmEmsR2=6.67×10-11N.m2/kg26×1024kg2×1030kg1.5×1011m2=3.55×1022N

The rate of change in momentum matches the force exerted on the Earth, as demonstrated by the data, which makes sense. The Earth's motion is virtually round, with the period repeating itself. As a result, the Earth's velocity and momentum are tangential, and the direction of change in momentum is toward the path's centre.

Thus, the force is directed toward the path's centre.

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