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3 years ago

Label these as balanced or unbalanced:

Physics

2 answers:

kvasek [131]3 years ago

4 0

Answer:

A book lying on a table - Balanced force
An airplane cruising in level flight - Balanced
A rock falling from a cliff - Unbalanced force
A bridge collapsing in an earthquake - Unbalanced force
A man sitting on a park bench - Balanced force
A space shuttle taking off - Unbalanced force
A car maintaining a constant speed on a straight road - Balanced force
An airplane landing - Unbalanced force

Explanation:

Usually, one or more forces act on a body at an instant of time. When these forces acting on a body and bring the body in the equilibrium position, the force is said to be balanced. The unbalanced force changes the equilibrium state of the body.

As in the case of an airplane cruising in a level flight, the weight of the plane will be equal to the lift force and the thrust is equal to the drag. So the plane is experiencing a balanced force.

erik [133]3 years ago

3 0

Answer:

1. A book lying on a table (Balanced force)

2.An airplane cruising in level flight (Balanced force)

3.A rock falling from a cliff (Unbalanced force)

4.A bridge collapsing in an earthquake (Unbalanced force)

5.A man sitting on a park bench (Balanced force)

6.A space shuttle taking off (Unbalanced force)

7.A car maintaining a constant speed on a straight road (Balanced force)

8.An airplane landing (Unbalanced force)

Explanation:

An object will be in equilibrium or balanced state if the sum off all the forces and toques on that object will be equal to zero.

in case of book lying on the table its weight is balanced by the normal force exerted by the table. So, balance force is acting on it. Same analogy can be applied to a man sitting on bench.

When air plane cruise in level flight, the weight of airplane is equal to the lift force and drag force is equal to the thrust force. Hence, balanced force acts on the airplane.

When car runs with the uniform speed on the road, engine force is equal to the frictional force. Hence, balanced force acts on the car.

In all other cases unbalance forces act which can be judged just by looking statements.

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Answer:

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Explanation:

Given data

$P_{a}=98kPa\\ p_{oil}=850kg/m^{3}\\ h=110cm=1.10m$

To find absolute pressure of air in the tank.We must find the pressure athe parallel point from the right tube

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3 years ago

Distinguish

yaroslaw [1]

Answer:

Velocity and speed both are continuously increasing.

Acceleration is constant.

Explanation:

Speed is defined as length of path covered by a body per unit time. Speed is a scalar quantity that consist of magnitude only and not direction.

Velocity is defined as the displacement per unit times. Displacement is the shortest distance between the two points. It is a vector quantity and hence has a direction in the direction of displacement along with its own magnitude.

Both velocity and speed have same unit of measure which is meter per second in S.I. During <em>free fall</em> in the absence of any air resistance the velocity and speed both will be having a vertical downward direction with continuously increasing magnitude. Tough we are not concerned about the direction when discussing about speed but here both are equal since the motion is linear.

Acceleration is the rate of change in velocity of a body which is a vector quantity. For speed we are concerned about instantaneous acceleration since for a short period of time it may have a specific direction.

During free fall the acceleration is of a body is equal to the acceleration due to gravity and constant when the height of fall is much lesser than the radius of the earth.

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3 years ago

A proton is moving toward a stationary charged particle. Which statement correctly describes an energy change that could occur a

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Answer:

Kinetic energy will be converted into electric potential energy if the stationary particle is positive.

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A 51 kg skater twirls at 0.64 rev/s with her arms extended. She then brings her arms in and twirls at 0.95 rev/s. The skater's m

DanielleElmas [232]

Answer:

(a) 1.09 kg m²

(b) 48.9 %

Explanation:

mass of skater, m = 51 kg

frequency when the arms are extended, f = 0.64 rev/s

frequency when the arms are in, f' = 0.95 rev/s

radius of cylinder when the arms in, r' = 17 cm

Moment of inertia of the body of skater when the arms in, I' = 0.5 x m x r'²

I' = 0.5 x 51 x 0.17 x 0.17 ² = 0.737 kg m²

(a)

By using the conservation of angular momentum

I x ω = I' x ω'

I x 2 x π x f = I' x 2 x π x f'

I x 0.64 = 0.737 x 0.95

I = 1.09 kg m²

Thus, the moment of inertia when the arms are in extended is 1.09 kg m².

(b)

Initial kinetic energy when the arms are extended, k = 0.5 x I x ω²

K = 0.5 x 1.09 x 4 x 3.14 x 3.14 x 0.64 x 0.64 = 8.8 J

Final kinetic energy when the arms are in, k' = 0.5 x I' x ω'²

K' = 0.5 x 0.737 x 4 x 3.14 x 3.14 x 0.95 x 0.95 = 13.1 J

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$\frac{K' - K}{K}\times 100=\frac{13.1 - 8.8 }{8.8 }\times 100$ = 48.9 %

Thus, the percentage change in kinetic energy is 48.9 %.

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