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3 years ago

Two objects must be in contact for them to exert a force on each other. True False

Physics

1 answer:

Irina-Kira [14]3 years ago

5 0

Answer:

False

Explanation:

The given statement "Two objects must be in contact for them to exert a force on each other" is not true as there are many types of forces that doesn't require being in contact for exerting a force.

One such example is the gravitational force acting between two bodies. Gravitational force is the force of pull with which a body pulls another body without being in contact.

For two bodies of masses 'M' and 'm' separated at a distance of 'R', the gravitational force is given as:

$Force=\frac{GMm}{R^2}\\Where,G\to \textrm{Universal Gravitational constant}$

The gravitational force acts always act between bodies that have mass. The bodies are not in contact yet experience force.

Therefore, the given statement is false.

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A 1000 kg satellite and a 2000 kg satellite follow exactly the same orbit around the earth. What is the ratio F1/F2 of the gravi

Tamiku [17]

Answer:

the ratio F1/F2 = 1/2

the ratio a1/a2 = 1

Explanation:

The force that both satellites experience is:

F1 = G M_e m1 / r² and

F2 = G M_e m2 / r²

where

m1 is the mass of satellite 1
m2 is the mass of satellite 2
r is the orbital radius
M_e is the mass of Earth

Therefore,

F1/F2 = [G M_e m1 / r²] / [G M_e m2 / r²]

F1/F2 = [G M_e m1 / r²] × [r² / G M_e m2]

F1/F2 = m1/m2

F1/F2 = 1000/2000

F1/F2 = 1/2

The other force that the two satellites experience is the centripetal force. Therefore,

F1c = m1 v² / r and

F2c = m2 v² / r

where

m1 is the mass of satellite 1
m2 is the mass of satellite 2
v is the orbital velocity
r is the orbital velocity

Thus,

a1 = v² / r ⇒ v² = r a1 and

a2 = v² / r ⇒ v² = r a2

Therefore,

F1c = m1 a1 r / r = m1 a1

F2c = m2 a2 r / r = m2 a2

In order for the satellites to stay in orbit, the gravitational force must equal the centripetal force. Thus,

F1 = F1c

G M_e m1 / r² = m1 a1

a1 = G M_e / r²

also

a2 = G M_e / r²

Thus,

a1/a2 = [G M_e / r²] / [G M_e / r²]

a1/a2 = 1

4 0

3 years ago

Santa doesn't want to push a 25.0 kg wooden box across a wooden floor with a uk of 0.20 at

scZoUnD [109]

Answer:

49 N

Explanation:

In order to move the box at constant speed, the acceleration of the box must be zero (a=0): this means, according to Newton's second law,

F = ma

that the net force acting on the box, F, must be zero as well.

Here there are two forces acting on the box in the horizontal direction while it is moving:

- The force of push applied by the guy, F

- The frictional force, $F_f$

For an object moving on a flat surface, the frictional force is given by

$F_f = \mu_k mg$

where

$\mu_k$ is the coefficient of friction

m is the mass of the box

g is the acceleration of gravity

So the equation of the forces becomes

$F-\mu_k mg = 0$

And substituting:

$\mu_k = 0.20\\m = 25.0 kg\\g = 9.8 m/s^2$

We find the force that must be applied by the guy:

$F=\mu_k mg = (0.20)(25.0)(9.8)=49 N$

6 0

3 years ago

Which of the following affect friction (you can choose more than 1)

Anastaziya [24]

I think it would be WEIGHT and ROUGHNESS OF SURFACE.

4 0

3 years ago

Read 2 more answers

The stomach lining is made up of deep muscular grooves.How might these structures help the stomach to break down food?

Sergio039 [100]

I really hope this could help u

7 0

3 years ago

I NEED HELP WITH THE LAST QUESTION PLS HELP!! (The one below 8)

maksim [4K]

Answer:

I. 6 cells .

II. Series connection.

Explanation:

I. Determination of the number of cells needed.

From the question given above,

Total voltage (V) = 9 V

1.5 V = 1 cell

Number of cells needed =?

The number of cells needed to make the 9V battery can be obtained as follow:

1.5 V = 1 cell

Therefore,

9 V = 9 V × 1 cell / 1.5 V

9 V = 6 cells

Thus, 6 cells of 1.5 V each is needed

II. Determination of the connection line

Total voltage (Vₜ) = 9 V

Cell 1 (V₁) = 1.5 V

Cell 2 (V₂) = 1.5 V

Cell 3 (V₃) = 1.5 V

Cell 4 (V₄) = 1.5 V

Cell 5 (V₅) = 1.5 V

Cell 6(V₆ ) = 1.5 V

For parrall connection:

Vₜ = V₁ = V₂ = V₃ = V₄ = V₅ = V₆

9 V = 1.5 V =... = 1.5 V

For series connection:

Vₜ = V₁ + V₂ + V₃ + V₄ + V₅ + V₆

9 = 1.5 + 1.5 + 1.5 + 1.5 + 1.5 + 1.5

9 V = 9 V

From the illustration above, we can see that series connection of each cells will give a total volt of 9 V unlike the parallel connection which resulted to 1.5 V.

Therfore, the cells should be arranged in series connection

8 0

3 years ago