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MariettaO [177]

2 years ago

15

Two friends of different masses are on the playground. They are playing on the seesaw and are able to balance it even though the

ir masses are different. show answer No Attempt How are they able to balance on the seesaw? They are able to balance their individual energies. All of these. Their densities are the same. They are able to balance forces due to gravity. They are able to balance their individual momenta. They are able to balance torques due to gravity.

1 answer:

Westkost [7]2 years ago

5 0

Answer:

They are able to balance torques due to gravity.

$F_1 L_1 = F_2L_2$

Explanation:

When two friends of different masses will balance themselves on see saw then at equilibrium position the see saw will remain horizontal

This condition will be torque equilibrium position where the see saw will not rotate

Here we can say

$F_1 L_1 = F_2L_2$

here we know that force is due to weight of two friends

and their positions are different with respect to the lever about which see saw is rotating

since both friends are of different weight so they will balance themselves are different positions as per above equation

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You drop your keys in a high-speed elevator going up at a constant speed. Part APart complete Do the keys accelerate faster towa

anzhelika [568]

Answer:

Explained

Explanation:

a) No, the keys were initially moving upward in the elevator only effects the initial velocity of the key and not the rate of change of velocity that is acceleration. So, the keys accelerate with the same acceleration as before.

b)Yes, keys will accelerate towards the floor faster if it is a constant speed than it is moving downward because if the elevator is accelerating downward, the downward change in velocity of the keys is at least partially matched by a downward change in the velocity of the of the elevator.

5 0

1 year ago

Two insulated copper wires of similar overall diameter have very different interiors. One wire possesses a solid core of copper,

balandron [24]

Answer with Explanation:

We are given that

Radius of solid core wire=r=2.28 mm= $2.28\times 10^{-3} m$

$1mm=10^{-3} m$

Radius of each strand of thin wire=r'=0.456 mm= $0.456\times 10^{-3} m$

Current density of each wire= $J=3750 A/m^2$

a.Area = $\pi r^2$

Where $\pi=3.14$

Using the formula

Cross section area of copper wire has solid core = $3.14\times (2.28\times 10^{-3})^2=16.3\times 10^{-6} m^2$

Current density = $J=\frac{I}{A}$

Using the formula

$3750=\frac{I}{16.3\times 10^{-6}}$

$I=3750\times 16.3\times 10^{-6}=0.061 A$

Total number of strands=19

Area of strand wire= $A'=19\times 3.14\times (0.456\times 10^{-3})^2=12.4\times 10^{-6} m^2$

$J'=\frac{I'}{A'}$

$3750=\frac{I'}{19\times 3.14(0.456\times 10^{-3})^2}$

$I'=3750\times 19\times 3.14(0.456\times 10^{-3})^2$

$I'=0.047 A$

b.Resistivity of copper wire= $\rho=1.69\times 10^{-8}\Omega-m$

Length of each wire =6.25 m

Resistance, R= $\frac{\rho l}{A}$

Using the formula

Resistance of solid core wire= $R=\frac{1.69\times 10^{-8}\times 6.25}{16.3\times 10^{-6}}=6.5\times 10^{-3}\Omega$

Resistance of strand wire= $R'=\frac{1.69\times 10^{-8}\times 6.25}{12.4\times 10^{-6}}=8.5\times 10^{-3}\Omega$

7 0

1 year ago

Harmonics problem. A square wave of frequency f contains harmonics (sine waves) at f, 3f, 5f, 7f, ... . Suppose a system respond

ira [324]

Answer:

B

Explanation:

A square of frequency of consists of the infinite sum of sine waves, whose frequencies are the odd multiples of the main frequency f i.e f, 3f,5f, 7f, ... . Given that the range of frequencies, to which the system responds is 20-40 kHz, for a square wave of frequency 10kHz we need to look for the harmonics whose frequencies are in the systems' respond range, which are the harmonics of 20, 30 and 40 kHz

4 0

1 year ago

An automobile being tested on a straight road is 400 feet from its starting point when the stopwatch reads 8.0 seconds and is 55

m_a_m_a [10]

Answer:

a) v = 75 ft / s , b) v = 55 ft / s , c) Δx = 1000 ft

Explanation:

We can solve this exercise with the expressions of kinematics

a) average speed is defined as the distance traveled in a given time interval

v = (x₂-x₁) / (t₂-t₁)

v = (550 - 400) / (10 -8)

v = 75 ft / s

b) we repeat the calculations for this interval

v = (550 - 0) / (10 -0)

v = 55 ft / s

c) we clear the distance from the average velocity equation

Δx = v (t₂ -t₁)

Δx = 100 (20-10)

Δx = 1000 ft

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1 year ago

The definition of theory says that a it is a hypothesis or group hypotheses. In your own words, explain why a theory is also a h

BigorU [14]

A hypothesis is a tentative and testable explanation, based on observation(s). A hypothesis can be supported or refuted through experimentation or more observation. A hypothesis can be disproven, but not proven to be true.

8 0

1 year ago

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