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3 years ago

15

From her bedroom window a girl drops a water-filled balloon to the ground, 4.60 m below. If the balloon is released from rest, h

ow long is it in the air?

1 answer:

anygoal [31]3 years ago

8 0

Known variables
d=4.6m
initial velocity=0m/s
downward acceleration=-9.8m/s2

d=1/2gt2
4.6=1/2 -9.8 t2
t=0.93s

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You are driving on a freeway and notice a small car (very small) cut off a big truck. Explain why it is a bad idea for the small

Leno4ka [110]

Answer: small cars can stop and go fast big trucks can not

Explanation:

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3 years ago

What element is found in liver and is needed to prevent anemia or tired blood

mel-nik [20]

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2 years ago

You are standing on a sidewalk. There is a car in the distance. The horn on the car sounds. You hear it at a pitch that correspo

AnnyKZ [126]

Answer: The answer: The car is moving away from you.

Both A and C are true as Car can be moving in line away from you or has component of velocity in opposite direction.

Explanation:The decrease in the frequency of the sound is the result of Doppler's effect. A/c to Doppler's effect the frequency of received sound of source is changed if it is moving relative to the receiver, i.e. the distance between them is changing due to motion.

The general formula of Doppler's Effect is attached as the picture.

In this formula v_D is the velocity of Detector i.e the receiver relative to wind. While v_s is the velocity of source relative to wind and v is the velocity of sound.

The Doppler's effect is not effected by the velocity of wind as the wind itself could not change the distance between the two objects i.e. you and the car. Wind velocity can change the speed of sound and its wavelength but the change does not effect the frequency.

Hence if we assume the car to be moving with velocity v_c and you are stationary

$f'=f_s*\frac{v}{v-v_c}$

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4 0

3 years ago

Considerable scientific work is currently under way to determine whether weak oscillating magnetic fields such as those found ne

VLD [36.1K]

Answer:

The the maximum emf is $2.52\times10^{-11}\ V$

Explanation:

Given that,

Magnetic field $B = 1.40\times10^{-3}\ T$

Frequency = 60 Hz

Diameter = 7.8 μm

We need to calculate the maximum emf

Using formula of emf

$\epsilon=NBA\omega$

Where, N = number of turns

B= magnetic field

A = area

Put the value in to the formula

$\epsilon=1\times1.40\times10^{-3}\times\pi\times(\dfrac{7.8\times10^{-6}}{2})^2\times2\times\pi\times60$

$\epsilon=2.52\times10^{-11}\ V$

Hence, The the maximum emf is $2.52\times10^{-11}\ V$

5 0

2 years ago

A sphere of radius 5.00 cmcm carries charge 3.00 nCnC. Calculate the electric-field magnitude at a distance 4.00 cmcm from the c

kogti [31]

Answer:

a) E = 8628.23 N/C

b) E = 7489.785 N/C

Explanation:

a) Given

R = 5.00 cm = 0.05 m

Q = 3.00 nC = 3*10⁻⁹ C

ε₀ = 8.854*10⁻¹² C²/(N*m²)

r = 4.00 cm = 0.04 m

We can apply the equation

E = Qenc/(ε₀*A) (i)

where

Qenc = (Vr/V)*Q

If Vr = (4/3)*π*r³ and V = (4/3)*π*R³

Vr/V = ((4/3)*π*r³)/((4/3)*π*R³) = r³/R³

then

Qenc = (r³/R³)*Q = ((0.04 m)³/(0.05 m)³)*3*10⁻⁹ C = 1.536*10⁻⁹ C

We get A as follows

A = 4*π*r² = 4*π*(0.04 m)² = 0.02 m²

Using the equation (i)

E = (1.536*10⁻⁹ C)/(8.854*10⁻¹² C²/(N*m²)*0.02 m²)

E = 8628.23 N/C

b) We apply the equation

E = Q/(ε₀*A) (ii)

where

r = 0.06 m

A = 4*π*r² = 4*π*(0.06 m)² = 0.045 m²

Using the equation (ii)

E = (3*10⁻⁹ C)/(8.854*10⁻¹² C²/(N*m²)*0.045 m²)

E = 7489.785 N/C

6 0

2 years ago