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ira [324]
3 years ago
7

Polly is pushing a box across the floor with a force of 30 N. The force of gravity is -8 N, and the normal force is 8 N. Which

Physics
1 answer:
wlad13 [49]3 years ago
5 0

Answer:

Force of friction is (-30 N).

Explanation:

The force applied on the  box across the floor is 30 N.

The force of gravity is (-8 N) and the the normal force is 8 N.

It is based on Newton's third law of motion. Newton's third law of motion states that the force acting on object 1 to object 2 is equal in magnitude of the force from object 2 to 1 but in opposite direction.

Here there is force of 30 N is applied in horizontal direction. The frictional force act in opposite direction. So, the force of friction is -30 N so that box across the floor.

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Explain the change of frequency of the wave if the tension of the string is increased​
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Answer:

Increasing the tension on a string increases the speed of a wave, which increases the frequency (for a given length). Pressing the finger at different places changes the length of string, which changes the wavelength of standing wave, affecting the frequency.

Explanation:

8 0
3 years ago
A book is launched up along the rough incline. Kinetic energy given to a book at initial point is 100 J. Book comes to stop at s
den301095 [7]

Answer:

(A) 60 J

Explanation:

At state 1

KE₁=100 J

At state 2

KE₂ = 0

U₂=80 J

Given that surface is rough so friction force will act in opposite to the direction of motion

Lets take work done by friction = Wfr

From work power energy

Work done by all forces = Change in kinetic energy

Wfr + U₂=ΔKE

Wfr+80 = 100

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Now when book slides from top position then

Wfr+ U = KEf - KEi

-20 + 80 = KEf-0

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(A) 60 J

7 0
3 years ago
Why are we not crushed by the weight of the atmosphere on our shoulders?
antiseptic1488 [7]

Answer:

Due to equal pressure in all the direction at a particular level in a fluid medium (Pascal's Law)

Explanation:

We are not crushed by the weight of the atmosphere because atmosphere is a fluid and we are immersed into it. So, according to the Pascal's law the the pressure a each point in a horizontal level is equal in all the direction irrespective of the orientation of a body.

Variation of pressure in term of the height of a fluid medium is given as:

P=\rho.g.h

\rho=density of fluid

g = acceleration due to gravity

h = height of the free surface of the fluid from the immersed object.

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At what speed does a 1400 compact car have the same kinetic energy as a 20000 truck going 25 ?
kumpel [21]
K=1400*V^2/2
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What is planned goal for the Europa clipper mission
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It's being planned to launch in the 2020's
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