A roller coaster pushes a 25 kg person upward with a force of 300 N. What is the acceleration?

A small glass bead has been charged to +20 nC. A small metal ball bearing 1.0 cm above the bead feels a 0.018 N downward electri

Alla [95]

Answer:

$q=1\times10^{-8}C$

Explanation:

Let the charge on the ball bearing is q.

charge on glass bead, Q = 20 nC = 20 x 10^-9 C

Force between them, F = 0.018 N

Distance between them, d = 1 cm = 0.01 m

By use of Coulomb's law in electrostatics

$F=\frac{KQq}{d^{2}}$

By substituting the values

$0.018=\frac{9\times10^{9}\times20\times10^{-9}q}{0.01^{2}}$

$q=1\times10^{-8}C$

Thus, the charge on the ball bearing is $q=1\times10^{-8}C$

7 0

3 years ago

How are the planets sizes related to their surface gravity

dexar [7]

Answer:

The surface gravity is inversely proportional to the square of the radius of the planet

Explanation:

The gravity at the surface of a planet is given by:

$g=\frac{GM}{R^2}$

where

G is the gravitational constant

M is the mass of the planet

R is the radius of the planet

We see from the formula that the surface gravity is inversely proportional to the square of the radius of the planet, R.

At the Earth's surface, the value of the surface gravity is approximately 9.81 m/s^2.

6 0

3 years ago

Which of the following is not a key assumption to the Scientific Method?

nataly862011 [7]

Answer:

D reliability

Explanation:

I think am collect but if you recognize that am wrong just collect me then

4 0

3 years ago

Describe how you expect the waveform and the sound you hear changes when you hit the tuning fork harder.

myrzilka [38]

Answer:

In a tuning fork, two basic qualities of sound are considered, they are

1) The pitch of the waveform: This pitch depends on the frequency of the wave generated by hitting the tuning fork.

2) The loudness of the waveform: This loudness depends on the intensity of the wave generated by hitting the tuning fork.

Hitting the tuning fork harder will make it vibrate faster, increasing the number of vibrations per second. The number of vibration per second is proportional to the frequency, so hitting the tuning fork harder increase the frequency. From the explanation on the frequency above, we can say that by increasing the frequency the pitch of the tuning fork also increases.

Also, hitting the tuning fork harder also increases the intensity of the wave generated, since the fork now vibrates faster. This increases the loudness of the tuning fork.

6 0

3 years ago

A stone is thrown straight up from the ground with an initial speed of 44 m/s.At the same instant, a stone is dropped from a hei

Lubov Fominskaja [6]

Answer:

394.26 m

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.8 m/s²

$v=u+at\\\Rightarrow 0=44-9.8\times t\\\Rightarrow \frac{-44}{-9.8}=t\\\Rightarrow t=4.49 \s$

$s=ut+\frac{1}{2}at^2\\\Rightarrow s=44\times 4.49+\frac{1}{2}\times -9.8\times 4.49^2\\\Rightarrow s=98.77\ m$

$s=ut+\frac{1}{2}at^2\\\Rightarrow 98.77=0t+\frac{1}{2}\times 9.8\times t^2\\\Rightarrow t=\sqrt{\frac{98.77\times 2}{9.8}}\\\Rightarrow t=4.49\ s$

Total time taken by the stone to reach the ground is 4.49+4.49 = 8.97 seconds

$s=ut+\frac{1}{2}at^2\\\Rightarrow h=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{h\times 2}{9.8}}$

The times are equal so,

$8.97=\sqrt{\frac{h\times 2}{9.8}}\\\Rightarrow h=\frac{8.97^2\times 9.8}{2}\\\Rightarrow h=394.26\ m$

The height is 394.26 m

6 0

3 years ago