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Black_prince [1.1K]
3 years ago
9

A branch falls from a tree How fast is the branch moving after 0 28 seconds

Physics
1 answer:
egoroff_w [7]3 years ago
3 0

Answer:

c. 2.7 m/s

Explanation:

v = a.t + v_{0}\\a = g = 9.81 m/s^{2}} \\t=0.28 s \\v_{0} = 0\\=> v = 9.81 * 0.28 = 2.74 m/s

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For a wire has a circular cross section with a radius of 1.23mm.
Mila [183]

Answer:

5.731\times 10^{-5}\ m/s

Decrease

Explanation:

I = Current = 3.7 A

e = Charge of electron = 1.6\times 10^{-19}\ C

n = Conduction electron density in copper = 8.49\times 10^{28}\ electrons/m^3

v_d = Drift velocity of electrons

r = Radius = 1.23 mm

Current is given by

I=neAv_d\\\Rightarrow v_d=\dfrac{I}{neA}\\\Rightarrow v_d=\dfrac{3.7}{8.49\times 10^{28}\times 1.6\times 10^{-19}\times \pi (1.23\times 10^{-3})^2}\\\Rightarrow v_d=5.731\times 10^{-5}\ m/s

The drift speed of the electrons is 5.731\times 10^{-5}\ m/s

v_d=\dfrac{I}{neA}

From the equation we can see the following

v_d\propto \dfrac{1}{n}

So, if the number of conduction electrons per atom is higher than that of copper the drift velocity will decrease.

5 0
3 years ago
An object is thrown with velocity v from the edge of a cliff above level ground. Neglect air resistance. In order for the object
musickatia [10]

Answer:

(C) greater than zero but less than 45° above the horizontal

Explanation:

The range of a projectile is given by R = v²sin2θ/g.

For maximum range, sin2θ = 1 ⇒ 2θ = sin⁻¹(1) = 90°

2θ = 90°

θ = 90°/2 = 45°

So the maximum horizontal distance R is in the range 0 < θ < 45°, if θ is the angle above the horizontal.

4 0
3 years ago
Read 2 more answers
Which of the following is the number of cycles per unit of time? infrasonis wave,frequency,ultrasonic wave or pitch
Allushta [10]
Frequency
Hope this helped :)
4 0
3 years ago
Read 2 more answers
A plane travels 2.5 KM at an angle of 35 degrees to the ground, then changes direction and travels 5.2 km at an angle of 22 degr
Solnce55 [7]

Answer:

7.7 km 26°

Explanation:

The total x component is:

x = 2.5 cos(35°) + 5.2 cos(22°) = 6.87

The total y component is:

y = 2.5 sin(35°) + 5.2 sin(22°) = 3.38

The magnitude is:

d = √(x² + y²)

d = 7.7 km

The direction is:

θ = atan(y/x)

θ = 26°

5 0
3 years ago
A lamp is rated for 240v,2.5A.what is the cost of using the lamp for 3hrs if 1kWh of electricity cost #12​
marshall27 [118]

Answer:

≈ 22¢

Explanation:

240 / 1000 = 0.240 kV

0.240 kV(2.5 A)(3 hr) = 1.8 kW•hr

1.8 kW•hr($0.12/kW•hr) = $0.216

6 0
3 years ago
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