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3 years ago

A 40 kg boy on a skateboard throws a 2 kg ball at 20 m/s to the left. How fast did the boy move to the right on his skateboard?

Physics

1 answer:

sergey [27]3 years ago

4 0

According to my examination I have confirmed that I do NOT repeat do NOT know this .

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Two balls of mass 0.09 kg hang on strings attached to the same point on the ceiling. The balls are given charges Q that cause th

telo118 [61]

Answer:

Q = 6.33μC

Explanation:

To find the value of the charge Q you take into account both gravitational force and electric force over each ball. By symmetry you can use the fact that both balls experiences the same forces. Hence you only take into account the forces for one ball for the x component and y component:

$-Mg+Tcos\theta=0\\\\F_e-Tsin\theta=0$

M: mass of the ball = 0.09kg

T: tension of the string

F_e: electric force between charges

angle = 45°

The electric force is given by:

$F_e=k\frac{Q^2}{r^2}$

Q: charge of the balls

r: distance between balls = 2m

You divide both equation in order to eliminate the tension T:

$tan\theta=\frac{F_e}{Mg}=k\frac{Q^2}{Mgr^2}$

By doing Q the subject of the formula and replacing you obtain:

$Q=\sqrt{\frac{tan\theta Mgr^2}{k}}=\sqrt{\frac{tan45\°(0.09kg)(2m)^2}{(8.89*10^{9}Nm^2/C^2)}}=6.33*10^{-6}C=6.33\mu C$

hence, the charge of the balls is 6.33μC

4 0

3 years ago

Question 16 of 20 You plan to use a slingshot to launch a ball that has a mass of 0.023 kg. You want the ball to accelerate stra

liubo4ka [24]

Answer:

this is a simple application of Newton's 2nd Law: F = ma.

F = 0.023(25)

So,

F =0.575 N.

Therefore

The answer is A.

If rounded up/off.

Explanation:

HOPE IT HELPS.

PLEASE MARK AS BRAINLIEST.

4 0

2 years ago

Calculate the location xcm of the center of mass of the Earth-Moon system. Use a coordinate system in which the center of the Ea

Jet001 [13]

Answer:

The center of mass of the Earth-Moon system is 4.673 kilometers away from center of Earth.

Explanation:

Let suppose that planet and satellite can be treated as particles. The masses of Earth and Moon ( $m_{E}$ , $m_{M}$ ) are $5.972\times 10^{24}\,kg$ and $7.349\times 10^{22}\,kg$ , respectively. The distance between centers is 384,403 kilometers. The location of the center of mass can be found by using weighted averages:

$\bar x = \frac{x_{E}\cdot m_{E}+x_{M}\cdot m_{M}}{m_{E}+m_{M}}$

If $x_{E} = 0\,km$ and $x_{M} = 384,403\,km$ , then:

$\bar x = \frac{(0\,km)\cdot (5.972\times 10^{24}\,kg)+(384,403\,km)\cdot (7.349\times 10^{22}\,kg)}{5.972\times 10^{24}\,kg+7.349\times 10^{22}\,kg}$

$\bar x = 4.673\,km$

The center of mass of the Earth-Moon system is 4.673 kilometers away from center of Earth.

8 0

3 years ago

Objects have a tendency to resist changing their motion. This property is called: *

Salsk061 [2.6K]

Answer:

The answer your looking for is option 2 - Inertia

3 0

3 years ago

The y-component of a projectile’s velocity is 12.1 m/s. When the projectile once again passes by the height from which it was la

Nat2105 [25]

It's 12.1 m/s, assuming that's the launch velocity that's given.
For projectile motion, velocity's y-component is parabolic/quadratic. It's x-component is constant, so you don't need to know it.

6 0

3 years ago