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3 years ago

15

Select the correct answer. What did Galileo discover when he dropped two cannon balls of different weights from the Leaning Towe

r of Pisa? A. The force acting on both of the balls was the same. B. The time for both of the balls to reach the ground was the same. C. A mass-dependent attractive force was exerted by Earth on the two balls. D. Gravity pulls everything downward. E. The balls exerted an attractive force between each other as they fell.

1 answer:

hoa [83]3 years ago

5 0

Galileo successfully demonstrated that the balls took the same amount of time to reach the ground.

Choice B

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Why does the moon have a stronger effect on tides than the sun?

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The moon is closer to the earth than the sun

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3 years ago

Scientists want to place a 3400.0 kg satellite in orbit around Mars. They plan to have the satellite orbit at a speed of 2480.0

BaLLatris [955]

Answer:

Part a)

$r = 6.96 \times 10^6 m$

Part b)

$F_g = 3.004 \times 10^3 N$

Part c)

$a = 0.88 m/s^2$

Part d)

$v = \frac{2480}{2} = 1240 m/s$

Explanation:

Part a)

As we know that the orbital speed of the satellite is given as

$v = 2480 m/s$

now we will have

$v = \sqrt{\frac{GM_{mars}}{r}}$

now we have

$M_{mars} = 6.4191 \times 10^{23} kg$

$R_{mars} = 3.397 \times 10^6 m$

now we have

$2480 = \sqrt{\frac{(6.67 \times 10^{-11})(6.4191 \times 10^{23})}{r}}$

$r = 6.96 \times 10^6 m$

Part b)

Here force between mars and satellite is the gravitational attraction force which is given as

$F_g = \frac{GM_{mars} m}{r^2}$

$F_g = \frac{(6.67\times 10^{-11})(6.4191 \times 10^{23})(3400)}{(6.96\times 10^6)^2}$

$F_g = 3.004 \times 10^3 N$

Part c)

Acceleration of satellite is the ratio of gravitational force and mass of the satellite

$a = \frac{F_g}{m}$

$a = \frac{3004}{3400}$

$a = 0.88 m/s^2$

Part d)

As we know by III law of kepler

$\frac{T_1^2}{T_2^2} = \frac{r_1^3}{r_2^3}$

here we know that T2 = 8 T1

$(\frac{1}{8})^2= \frac{r_1^3}{r_2^3}$

$\frac{r_1}{r_2} = (\frac{1}{2})^2$

so we have

$r_2 = 4r_1$

as we know that speed is given as

$v = \sqrt{\frac{GM}{r}}$

so we can say since radius is orbit becomes 4 times so the orbital speed must be half

$v = \frac{2480}{2} = 1240 m/s$

7 0

4 years ago

A rolling ball has 8 joules of kinetic energy and is rolling 4m/s. Find it’s mass

Maru [420]

Answer:

m = 1

Explanation:

K.E = 8J

v = 4m/s

m = ?

Now,

K.E = 1÷2mv^2

8 = 1÷2 × m × (4)^2

8 = 1÷2 × m × 16

8 = m × 8

m × 8 = 8

m = 8 ÷ 8 = 1

m = 1

<h3><em><u>VERIFICATION</u></em><em><u>:</u></em></h3>

K.E. = 1÷2mv^2

K.E = 1÷2 × 1 × 4^2

K.E. = 8J

<u>-TheUnknownScientist</u>

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3 years ago

The electric field inside a cell membrane is 8.0 MN/C. Part A What's the force on a singly charged ion in this field?

dlinn [17]

Answer:

Force on the singly charged ion will be $12.6\times 10^{-13}N$

Explanation:

We have given electric field E = 8 MN/C

So electric field in N/C will be $E=8MN/C=8\times 10^6N/C$

It is given that ion so charge on ion will be equal to $e=1.6\times 10^{-19}C$

We have to find the electric force on the ion

Electric force is equal to $F=qE$ , here q is charge and E is electric field

So force on the charge will be equal to $F=8\times 10^6\times 1.6\times 10^{-19}=12.6\times 10^{-13}N$

So force on the singly charged ion will be $12.6\times 10^{-13}N$

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4 years ago