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3 years ago

I really don't understand any of this because my teacher does not help us

Physics

1 answer:

LUCKY_DIMON [66]3 years ago

5 0

1. A. Greater than because displacement is zero

2. D. Position because velocity is distance/time

3. A. Instantaneous

4. B. Velocity because it has a speed and direction

5. D. S = D/T because speed is distance over time

6. A. Velocity because although speed is constant, direction is changing

7. C. Velocity

8. D. First negative, then position

9. D. Zero because the slope of velocity is acceleration

10. B. Inertia

11. A. Air resistance because it is the force pushing up on the object

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"My distance to the center of the earth is about 4000 miles when I am on the surface. If I go to a height of 8000 miles above th

lord [1]

Given,

Distance from the surface to the center of the earth, d=4000 miles

Distance from the center to you at a height of 8000 miles, a= 8000+4000=12000 miles

The gravitational force acting on a person at the surface is equal to his weight.

From Newton's Universal Law of Gravitation, the gravitational force is

$F=\frac{G\times M\times m}{r^2}$

Where G is the gravitational constant, M is the mass of the earth, m is the mass of the object/person, r is the distance between the center of the earth and the object/person

At the surface, this force is equal to the weight of the person, W=mg

i.e.

$F_s=\frac{G\times M\times m}{d^2}=W$

On substituting the of d,

$W=\frac{\text{GMm}}{4000^2}$

At a height of 8000 miles from the surface, the gravitational force is equal to,

$F_a=\frac{GMm}{12000^2}$

On dividing the above two equations,

$\frac{F_a}{W}=\frac{4000^2^{}}{12000^2}=\frac{1}{9}$

Therefore,

$F_a=\frac{1}{9}W$

Therefore at a height of 8000 miles above the surface of the earth, the force of gravity becomes 1/9 time your weight.

5 0

1 year ago

Starting from rest, a 6.79 kg block slides 2.82 m down a rough 20.7 ◦ incline. The coefficient of kinetic friction between the b

Veronika [31]

Answer:

23.52092 J

Explanation:

m = Mass of block = 6.79 kg

s = Sliding distance = 2.82 m

$\theta$ = Angle of slide = 20.7°

$\mu$ = Coefficient of kinetic friction = 0.425

g = Acceleration due to gravity = 9.8 m/s²

Work done by the force of gravity is given by

$W=mgsin\theta\\\Rightarrow W=6.79\times 9.8\times sin20.7\\\Rightarrow W=23.52092\ J$

The work done by the force of gravity is 23.52092 J

8 0

2 years ago

A long, current-carrying solenoid with an air core has 1800 turns per meter of length and a radius of 0.0165 m. A coil of 210 tu

Hoochie [10]

Answer:

The mutual inductance is $M = 0.000406 \ H$

Explanation:

From the question we are told that

The number of turns per unit length is $N = 1800$

The radius is $r = 0.0165 \ m$

The number of turns of the solenoid is $N_s = 210 \ turns$

Generally the mutual inductance of the system is mathematically represented as

$M = \mu_o * N * N_s * A$

Where A is the cross-sectional area of the system which is mathematically represented as

$A = \pi * r^2$

substituting values

$A = 3.142 * (0.0165)^2$

$A = 0.0008554 \ m^2$

also $\mu_o$ is the permeability of free space with the value $\mu_o = 4\pi * 10^{-7} N/A^2$

$M = 4\pi * 10^{-7} *1800 * 210 * 0.0008554$

$M = 0.000406 \ H$

3 0

3 years ago

Rainwater draining from a neighborhood street initially travels at 4 ft/s through a pipe with a cross-sectional area of 15.7 ft2

Fudgin [204]

Answer:

The velocity is $v_2 = 0.96 \ ft/s$

Explanation:

From the question we are told that

The initial speed is $v_1 = 4 \ ft/s$

The cross -sectional area of the first pipe is $A_1 = 15.7 \ ft$

The cross -sectional area of the second pipe is $A_2 = 65.4 \ ft$

Generally from continuity equation we have that

$A_1 * v_1 = A_2 * v_2$

$v_2 = \frac{A_1 * v_1 }{A_2 }$

=> $v_2 = \frac{15.7 * 4 }{65.4 }$

=> $v_2 = 0.96 \ ft/s$

6 0

3 years ago

Calculate the rotational inertia of a wheel that has akinetic

andrew11 [14]

Answer:

J = 14.4 kg*m^2

Explanation:

Assuming that the wheel is not moving anywhere, and the kinetic energy is only due to rotation:

Ek = 1/2 * J * w^2

J = 2 * Ek / (w^2)

We need the angular speed in rad / s

566 rev/min * (1 min/ 60 s) * (2π rad / rev) = 58.22 rad/s

Then:

J = 2 * 24400 / (58.22^2) = 14.4 kg*m^2

4 0

3 years ago