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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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Two wooden crates rest on top of one another. The smaller top crate has a mass of m1 = 25 kg and the larger bottom crate has a m

faust18 [17]

Answer:

Explanation:

Let the bigger crate be in touch with the ground which is friction less. In the first case both m₁ and m₂ will move with common acceleration because m₁ is not sliding over m₂.

1 ) Common acceleration a = force / total mass

= 234 / ( 25 +91 )

= 2.017 m s⁻².

2 ) Force on m₁ accelerating it , which is nothing but friction force on it by m₂

= mass x acceleration

= 25 x 2.017

= 50.425 N

The same force will be applied by m₁ on m₂ as friction force which will act in opposite direction.

3 ) Maximum friction force that is possible between m₁ and m₂

= μ_s m₁g

= .79 x 25 x 9.8

= 193.55 N

Acceleration of m₁

= 193 .55 / 25

= 7.742 m s⁻²

This is the common acceleration in case of maximum tension required

So tension in rope

= ( 25 +91 ) x 7.742

= 898 N

4 ) In case of upper crate sliding on m₂ , maximum friction force on m₁

= μ_k m₁g

= .62 x 25 x 9.8

= 151.9 N

Acceleration of m₁

= 151.9 / 25

= 6.076 m s⁻².

6 0

3 years ago

A coin completes 18 spins in 12 seconds. The centripetal acceleration of the edge of the coin is 2.2 m/s2. The radius of the coi

stellarik [79]

Answer:

2.5 cm

Explanation:

Number of spins in 12 seconds = 18

Number of spins in 1 second = 18 / 12 = 1.5

Number of spins in one second is called frequency.

f = 1.5 rps

ac = 2.2 m/s^2

Let r be the radius of coin

Centripetal acceleration, ac = r x w^2

2.2 = r x ( 2 x 3.14 x 1.5) ^2

2.2 = r x 88.7364

r = 0.025 m = 2.5 cm

3 0

3 years ago

Read 2 more answers

During a move, Jonas and Matías carry a 115kg safe to the third floor of a building, covering a height of 6.6m.

neonofarm [45]

Answer:

work is =7590joules

power = 23watts

4 0

3 years ago

Read 2 more answers

Runner A is initially 5.7 km west of a flagpole and is running with a constant velocity of 8.9 km/h due east. Runner B is initia

Oksanka [162]

Answer:

B meet A 0.01 km east of flagpole

Explanation:

given data

distance A = 5.7 km west

velocity V1 = 8.9 km/h

distance B = 4.5 km east

velocity V2 = 7 km/h

to find out

How far runners from the flagpole, when paths cross

solution

we know A and B are 5.7 + 4.5 = 10.2 km apart

and we consider here B will run distance x km for meet

so time will be for B is

time B = distance / velocity

time B = x / 7 ...................1

and

for A distance for meet = ( 10.2 - x ) km

so time A = distance / velocity

time A = ( 10.2 - x ) / 8.9 .............2

now equating equation 1 and 2

time A = time B

x / 7 = ( 10.2 - x ) / 8.9

x = 4.490

so distance of B run for meet is 4.490 km

so distance from the flagpole when their paths cross is 4.5 - 4.490 = 0.01 km

so B meet A 0.01 km east of flagpole

4 0

3 years ago

A hummingbird flies forward and backward. Its motion is shown on the above graph of horizontal Position and

harina [27]

Answer:

The hummingbird travels the total distance is 10 m

Explanation:

Given that,

A hummingbird flies forward and backward.

According to figure,

We know that,

The total distance is equal to the sum of all distance.

Forward direction is positive and backward direction is negative.

We need to calculate the hummingbird travels the total distance

Using figure,

$D=d_{1}+d_{2}+d_{3}+d_{4}$

Put the value into the formula

$D=6+(-4)+2+6$

$D=10\ m$

Hence, The hummingbird travels the total distance is 10 m.

8 0

3 years ago