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Tpy6a [65]
3 years ago
7

The 0.4-lb ball and its supporting cord are revolving about the vertical axis on the fixed smooth conical surface with an angula

r velocity of 4 rad /sec. The ball is held in the position b = 14 in. by the tension T in the cord. If the distance b is reduced to the constant value of 9 in. by increasing the tension T in the cord, compute the new angular velocity and the work W1-2 done on the system by T
Physics
1 answer:
solong [7]3 years ago
3 0

Answer:

Explanation:

In the whole process , angular momentum will be conserved because no external torque is acting on the system . The radius of circular path is reduced so angular velocity will be increased

I₁ x ω₁ = I₂ x ω₂

m r₁² x ω₁ = m r₁²ω₂

r₁² x ω₁ =  r₂²ω₂

ω₂ = r₁² x ω₁  /  r₂²

= ( 14 x 14 x 4) / ( 9 x 9 )

= 9.68 rad /s

Work done

= increase in rotational kinetic energy

= 1/2 x I₂ ω₂² - 1/2 x I₁ ω₁²        ( I = m r² )

=  1/2 x .4 x .454 x( 9 x 2.54 x 10⁻² x 9.68 )² - 1/2 x .4 x .454 x( 14 x 2.54 x 10⁻² x 4 )²

=   .4446 - 0.1837

= .261 J .

=

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A small box is held in place against a rough vertical wall by someone pushing on it with a force directed upward at 27 ∘ above t
ycow [4]

Answer:

Explanation:

Applied force, F = 18 N

Coefficient of static friction, μs = 0.4

Coefficient of kinetic friction, μs = 0.3

θ = 27°

Let N be the normal reaction of the wall acting on the block and m be the mass of block.

Resolve the components of force F.

As the block is in the horizontal equilibrium, so

F Cos 27° = N

N = 18 Cos 27° = 16.04 N

As the block does not slide so it means that the syatic friction force acting on the block balances the downwards forces acting on the block .

The force of static friction is μs x N = 0.4 x 16.04 = 6.42 N   .... (1)

The vertically downward force acting on the block is mg - F Sin 27°

                                                      = mg - 18 Sin 27° = mg - 8.172    ... (2)

Now by equating the forces from equation (1) and (2), we get

mg - 8.172 = 6.42

mg = 14.592

m x 9.8 = 14.592

m = 1.49 kg

Thus, the mass of block is 1.5 kg.  

6 0
3 years ago
What two types of scientific knowledge can be expressed as mathematical equations? (Please don't tell me the answer could you pl
gtnhenbr [62]
An example would be 2 types of motion. It could be rectilinear or projectile motion. There are various equations for each type. Since you don't want me to tell you the answer, I could just express it in words. Then, it will be up to you to translate into mathematical equations.

For rectilinear motion, the distance traveled is equal to the initial velocity times the time, plus one-half of the acceleration times the square of the time. For projectile motion, the maximum distance is equal to the square of the initial velocity multiplied with the square of the sine of the launch angle, all over twice the gravity.
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An escalator is used to move 25 passengers every minute from the first floor of a department store to the second. The second flo
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Answer:

55960 J

Explanation:

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nikitadnepr [17]

Answer:

B. Developed out of efforts of man trying to explain our physical environment.

Explanation:

This is because physics, as we all know of, is considered to be <em>crucial to understanding the world around us</em>, making it the most basic and fundamental of science.

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3 years ago
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Does exists the friction force in space?If yes,tell an full example
VashaNatasha [74]
Yes, friction does exist in space. Friction has nothing to do with the earth's atmosphere. It exists everywhere in the universe. <span />
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