**Answer:**

a)The gravitational force would be twice as much as it is now

**Explanation:**

If the earth had twice its mass as it is now, the gravitational force between the sun and the earth would be twice as much as it is now.

According to Newton's law of universal gravitation "the gravitational force of attraction between bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them".

F =

G is the universal gravitation constant

m is the mass

r is the distance

let mass of sun = s

mass of earth = e

new mass of sun = s

new mass of sun = 2e

input variables;

F = ------ i

F = ------- ii

From the second equation;

2F =

2F = F

Therefore, the force will double.

The 'plum pudding' model of the atom was proposed by JJ Thomson, who had also discovered the electron. It was put forth before the discovery of the nucleus. According to this model, the atom is a sphere of positive charge, and negatively charged electrons are embedded in it to balance the total positive charge

**Answer:**

a) tires rubbing, b) the weight has a component parallel to the floor

c) he child's back support, d) The tension of the rope and weight

**Explanation:**

In this exercise, we are asked to indicate the origin of the forces for the centripetal movement parallel to the rope, e) gravitational force

a) When a car turns, the centripetal force has two origins

* The tires rubbing against the road

* If the road has a lean angle, the component of the weight directed towards the center of the circle also contributes to the centripetal force.

b) the child in general has some degree of inclination with respect to the post, for which the weight has a component parallel to the floor that is responsible for the centripetal movement of the system

c) The bench rotates together with the carousel, so the child's back support is the response to the centripetal force

d) The tension of the rope has two components: the component perpendicular to the movement and the component of the weight (parallel to the rope) the difference of these two forces is the centripetal force

e) The gravitational force of the sun on the earth is what creates the centripetal motion

**Answer:**

ρ = 4.4 10⁻⁸ Ω m

**Explanation:**

For this exercise let's start by finding the value of the resistance using Ohm's law

V = I R

R = V / I

The voltage is related to the electric field

V = E L

let's substitute

R = E L / I

R = 8.2 10⁻² / 20

R = 4.1 10⁻³ L

now we can use the resistance relation

R = ρ L / A

the area of a circular wire is

A = π r² = π d² / 4

ρ = R π d² / (4 L)

let's calculate

ρ = (4.1 10⁻³ L) π 0.0037² / (4 L) = (4.1 10⁻³) π 0.0037² / (4)

ρ = 4.4 10⁻⁸ Ω m

**Answer:**

The average component velocity is 32.5 m/s

**Explanation:**

v = u +at bhjklj kj h

x = (u + v / 2 )t

Average velocity is given by

From the question,

Initial speed, u = 28 m/s

Final speed, v = 37 m/s

Time, t = 10 secs

From the formula

where is the displacement

Put the given values into the equation to find the displacement

Now, for the average component velocity

Hence, the average component velocity is 32.5 m/s