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3 years ago

A parent swings a 13.5 kg child

Physics

1 answer:

solmaris [256]3 years ago

3 0

The speed of the child is 2.21 m/s

Explanation:

The child is moving in circular motion. First of all, we find its frequency of revolution, which is given by:

$f=\frac{N}{t}$

where

N = 11 is the number of revolutions

t = 25.4 s is the time elapsed

So,

$f=\frac{11}{25.4}=0.433 Hz$

Now we find the angular frequency, which is given by

$\omega = 2\pi f = 2\pi(0.433)=2.72 rad/s$

And now we can fidn the linear speed of the child, which is given by

$v=\omega r$

where

$\omega=2.72 rad/s$ is the angular frequency

r = 0.811 m is the radius of the circular trajectory

Substituting,

$v=(2.72)(0.811)=2.21 m/s$

Learn more about circular motion:

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A 0.290 cm diameter plastic sphere, used in a static electricity demonstration, has a uniformly distributed 30.0 pC charge on it

mojhsa [17]

Answer:

Therefore,

The potential (in V) near its surface is 186.13 Volt.

Explanation:

Given:

Diameter of sphere,

d= 0.29 cm

$radius=\dfrac{d}{2}=\dfrac{0.29}{2}=0.145\ cm$

$r = 0.145\ cm = 0.145\times 10^{-2}\ m$

Charge ,

$Q = 30.0\ pC=30\times 10^{-12}$

To Find:

Electric potential , V = ?

Solution:

Electric Potential at point surface is given as,

$V=\dfrac{1}{4\pi\epsilon_{0}}\times \dfrac{Q}{r}$

Where,

V= Electric potential,

ε0 = permeability free space = 8.85 × 10–12 F/m

Q = Charge

r = Radius

Substituting the values we get

$V=\dfrac{1}{4\times 3.14\times 8.85\times 10^{-12}}\times \dfrac{30\times 10^{-12}}{0.145\times 10^{-2}}$

$V=\dfrac{30}{16.117\times 10^{-2}}=186.13\ Volt$

Therefore,

The potential (in V) near its surface is 186.13 Volt.

3 0

4 years ago

Which of the following describes the least amount of work being done? A. wind turning a windmill B. a batter hitting a baseball

Mandarinka [93]

Answer:

a ball hanging from a tall pole

Explanation:

work is force times a distance in the direction of the force. The ball just hanging there has no motion, so is associated with no work. Work was probably done in the hanging process, but none after.

6 0

3 years ago

Read 2 more answers

How long will it take for a car to travel 200 km if it has an average speed of 55 km/hr?

andreyandreev [35.5K]

Answer: Approximately 3.65 hours

Explanation:

55 km/h x 3.65 hrs = 200.75 Km/h

4 0

3 years ago

Six automobiles are initially traveling at the indicated velocities. The automobiles have different masses and velocities. The d

KIM [24]

Answer:

a)Car E = Car D > (Car F = Car B = Car C) > Car A

b)Car E = Car D > (Car F = Car B = Car C) > Car A

Explanation:

Car A: mass = 500 kg; speed = 10 m/s

Car B: mass = 2000 kg;speed = 5 m/s

Car C:mass = 500 kg; speed = 20 m/s

Car D: mass = 1000 kg; speed = 20 m/s

Car E:mass = 4000 kg; speed = 5 m/s

Car F: mass = 1000 kg; speed = 10 m/s

Part a) Now we know that momentum of each car is product of mass and velocity , so we will have

CarA:

$P_1 = m \times v\\P_1 = (500)(10)\\P_1 = 5 \times 10^3 kg m/s$

Car B:

$P_2 = m v\\P_2 = (2000)(5)\\P_2 = 10^4 kg m/s$

Car C:

$P_3 = m v\\P_3 = (500)(20)\\P_3 = 10^4 kg m/s$

Car D:

$P_4 = m v\\P_4 = (1000)(20)\\P_4 = 2\times 10^4 kg m/s$

Car E:

$P_5 = m v\\P_5 = (4000)(5)\\P_5 = 2\times 10^4 kg m/s$

Car F:

$P_6 = m v\\P_6 = (1000)(10)\\P_6 = 10^4 kg m/s$

So the momentum is given as ,

Car E = Car D > (Car F = Car B = Car C) > Car A

Part b)Impulse is given as change in momentum so here we can say that final momentum of all the cars will be zero as they all stops and hence the impulse is same as initial momentum of the car

so the order of impulse from largest to least is given as

Car E = Car D > (Car F = Car B = Car C) > Car A

3 0

3 years ago

a battery is connected to a resistor. as charge flows, the chemical energy of the battery is dissipated as _________.

balandron [24]

As charge flows, the chemical energy of the battery is dissipated as the time of charge flow increases.

Electric power is defined as the rate at which electric energy is dissipated.

The power of the current flowing through the circuit is calculated as follows;

P = IV

P = I x IR

P = I²R

where;

P is the power dissipated
I is the current flowing in the circuit
R is the resistance of the circuit

The electric energy is given as;

E = Pt

E = I²Rt

Thus, we can conclude that as charge flows, the chemical energy of the battery is dissipated as the time of charge flow increases.

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3 years ago