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dimulka [17.4K]

3 years ago

7

A 1 kg object sits on the earth’s surface. What is the force of gravity between the object and the earth? (mass of the earth = 5

.97 x 10 24kg, radius of the earth = 6.37 x 10 6m)

1 answer:

snow_lady [41]3 years ago

4 0

Answer:

9.81N

Explanation:

the force of attraction is given by

F=<u>GmM</u><u>/</u><u>R²</u><u> </u>

where m is mass of the body

M is mass of the earth

R is radius of the earth

G is the universal gravitational constant(6.67x10-¹¹)

hence we substitute the values in the formula.

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You want to find out how much water an aquarium tank can hold. Which SI unit would you use?

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U would have to use volume

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4 years ago

Read 2 more answers

Two Earth satellites, A and B, each of mass m, are to be launched into circular orbits about Earth's center. Satellite A is to o

Juliette [100K]

(a) 0.473

The potential energy of a satellite orbiting around Earth is given by

$U=-\frac{GMm}{R+h}$

where

G is the gravitational constant

M is the Earth's mass

m is the satellite's mass

R is the Earth's radius

h is the altitude of the satellite above the Earth's surface

So the potential energy of satellite A is

$U_A=-\frac{GMm}{R+h_A}$

while potential energy of satellite B is

$U_B=-\frac{GMm}{R+h_B}$

Therefore the ratio of the potential energy of satellite B to that of satellite A is

$\frac{U_B}{U_A}=\frac{R+h_A}{R+h_B}$

and using

hA = 5920 km

hB = 19600 km

R = 6370 km

we find

$\frac{U_B}{U_A}=\frac{6370+5920}{6370+19600}=0.473$

(b) 0.473

The kinetic energy of a satellite orbiting around Earth instead is given by

$K=\frac{GMm}{2(R+h)}$

So the kinetic energy of satellite A is

$K_A=\frac{GMm}{2(R+h_A)}$

while kinetic energy of satellite B is

$K_B=\frac{GMm}{2(R+h_B)}$

Therefore the ratio of the kinetic energy of satellite B to that of satellite A is

$\frac{K_B}{K_A}=\frac{R+h_A}{R+h_B}$

which is identical to before, so it gives

$\frac{K_B}{K_A}=\frac{6370+5920}{6370+19600}=0.473$

(c) Satellite B

The total energy of a satellite in orbit is given by

$E=U+K = -\frac{GMm}{R+h}+\frac{GMm}{2(R+h)}=-\frac{GMm}{2(R+h)}$

We see that the total energy is:

1) negative (because the satellite is on a bound orbit)

2) inversely proportional to the distance of the satellite from the Earth's center, R+h

So the magnitude of the fraction in the equation is larger for the satellite which is closer to the Earth's surface (satellite A), but since the energy is negative, this means that the total energy of this satellite is smaller than that of satellite B. So, satellite B has a greater total energy.

(d) $1.03\cdot 10^7 J$

We have to calculate the total energy of each satellite.

Given:

$G=6.67\cdot 10^{-11}$

$M=5.98\cdot 10^{24} kg$

m = 12.0 kg

$R+h_A = 6370 km+5920 km=12290 km = 12.3 \cdot 10^6 m$

$R+h_B = 6370 km+19600 km=25970 km = 26.0 \cdot 10^6 m$

We find:

$E_A = - \frac{(6.67\cdot 10^{-11})(5.98\cdot 10^{24})(12.0)}{2(12.3\cdot 10^6)}=-1.95\cdot 10^{7} J$

$E_B = - \frac{(6.67\cdot 10^{-11})(5.98\cdot 10^{24})(12.0)}{2(26.0\cdot 10^6)}=-9.2\cdot 10^{6} J$

So the difference in total energy is

$E_B-E_A = -9.2\cdot 10^6 - (-1.95\cdot 10^7) =1.03\cdot 10^7 J$

6 0

4 years ago

A boy jumps from rest, straight down from the top of a cliff. He falls halfway down to the water below in 0.883 s. How much time

Salsk061 [2.6K]

Answer:

1.25 s

Explanation:

We are given that

Initial velocity of boy=u=0

Time=0.883 s

Let x be the total distance covered by boy in entire trip.

s= $\frac{x}{2}$

We know that

$s=ut+\frac{1}{2}gt^2$

Where $g=10m/s^2$

Substitute the values

$\frac{x}{2}=0\times 0.883+\frac{1}{2}(10)(0.883)^2$

$\frac{x}{2}=3.898$

$x=3.898\times 2=7.796$ m

Again using the above formula

$7.796=0(t)+\frac{1}{2}(10)t^2$

$7.796=5t^2$

$t^2=\frac{7.796}{5}=1.5592$

$t=\sqrt{1.5592}=1.25 s$

Hence, 1.25 s passes during his entire tripe from the top down to the water.

8 0

3 years ago

A small styrofoam ball with a layer of metallic coating is lowered into the gap between two large metal plates. A large potentia

Brut [27]

Answer:

ball will oscillate in between the plates

Explanation:

The metallic coated styrofoam lowered in between two large metal plates, a large potential difference V is kept between the two plates, will experience a force of repulsion ( because both plates and balls will have similar kind of charges and like charges repel each other) from the opposite plates.

If we consider d as the distance between the plates, E as electric field because of Potential difference V. Then force F experience by the ball will be

$F= \frac{qV}{d}$

where q be the total charge on the metallic coated ball.

clearly, since, both the plates will repel the ball in opposite directions, hence ball will be in oscillate in between the plates.

3 0

4 years ago

A metal cube measures 15 cm on a side and has a density of 6920 kg/m^3. Find the mass in grams.

soldi70 [24.7K]

Answer:

Mass of the cube is 23350 grams.

Explanation:

It is given that,

Side of cube, a = 15 cm = 0.15 m

Density of the cube, $d=6920\ kg/m^3$

We need to find its mass. It can be calculated using the formula of density as :

$d=\dfrac{m}{V}$

$m=d\times V$ , V is the volume of cube

$m=d\times a^3$

$m=6920\ kg/m^3\times (0.15\ m)^3$

m = 23.35 kg

or

m = 23350 grams

So, the mass of the metal cube is 23350 grams. Hence, this is the required solution.

8 0

3 years ago