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3 years ago

9

Your friend is on rollerblades holding a pendulum. You gently push her forward and let go. You observe that the pendulum first s

wings in the opposite direction (backward) and then returns to the vertical orientation as she coasts forward.
Part A
Choose the correct force diagram of the pendulum bob (in inertial reference flame) as your friend is being pushed. y-direction is the vertical direction.

1 answer:

kodGreya [7K]3 years ago

8 0

It would be using Newton's First Law. Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. It may be seen as a statement about inertia, that objects will remain in their state of motion unless a force acts to change the motion.

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What type of eclipse is shown? How do you know?

Sonja [21]

That is a lunar eclipse. At night, when the Earth is between the Sun and the moon, the moon would appear to be red. Just for future reference, a solar eclipse is when the Moon is between the Sun and Earth. Speaking of which, check out the solar eclipse this August!

8 0

4 years ago

Read 2 more answers

A charge of 32.0 nC is placed in a uniform electric field that is directed vertically upward and has a magnitude of 4.30x 104 V/

hodyreva [135]

A) The work done by the electric field is zero

B) The work done by the electric field is $9.1\cdot 10^{-4} J$

C) The work done by the electric field is $-2.4\cdot 10^{-3} J$

Explanation:

A)

The electric field applies a force on the charged particle: the direction of the force is the same as that of the electric field (for a positive charge).

The work done by a force is given by the equation

$W=Fd cos \theta$

where

F is the magnitude of the force

d is the displacement of the particle

$\theta$ is the angle between the direction of the force and the direction of the displacement

In this problem, we have:

The force is directed vertically upward (because the field is directed vertically upward)
The charge moves to the right, so its displacement is to the right

This means that force and displacement are perpendicular to each other, so

$\theta=90^{\circ}$

and $cos 90^{\circ}=0$ : therefore, the work done on the charge by the electric field is zero.

B)

In this case, the charge move upward (same direction as the electric field), so

$\theta=0^{\circ}$

and

$cos 0^{\circ}=1$

Therefore, the work done by the electric force is

$W=Fd$

and we have:

$F=qE$ is the magnitude of the electric force. Since

$E=4.30\cdot 10^4 V/m$ is the magnitude of the electric field

$q=32.0 nC = 32.0\cdot 10^{-9}C$ is the charge

The electric force is

$F=(32.0\cdot 10^{-9})(4.30\cdot 10^4)=1.38\cdot 10^{-3} N$

The displacement of the particle is

d = 0.660 m

Therefore, the work done is

$W=Fd=(1.38\cdot 10^{-3})(0.660)=9.1\cdot 10^{-4} J$

C)

In this case, the angle between the direction of the field (upward) and the displacement (45.0° downward from the horizontal) is

$\theta=90^{\circ}+45^{\circ}=135^{\circ}$

Moreover, we have:

$F=1.38\cdot 10^{-3} N$ (electric force calculated in part b)

While the displacement of the charge is

d = 2.50 m

Therefore, we can now calculate the work done by the electric force:

$W=Fdcos \theta = (1.38\cdot 10^{-3})(2.50)(cos 135.0^{\circ})=-2.4\cdot 10^{-3} J$

And the work is negative because the electric force is opposite direction to the displacement of the charge.

Learn more about work and electric force:

brainly.com/question/6763771

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brainly.com/question/4273177

#LearnwithBrainly

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3 years ago

An automobile accelerates 1.77 m/s2 over 6.00 s to reach freeway speed at the end of an

GaryK [48]

Answer:

Startinfg speed is 13.82 m/s

Explanation:

Use equation for realtion between start and final speed :

Vf=Vs+a*t

Vf-final speed

Vs-start speed

Vf=24.44m/s

a=1.77m/s²(acceleration)

t=6.00s(Time)

Vf=Vs+a*t

Vs=a*t-Vf

Vs=1.77m/s²*6s-24.44m/s

Vs=-13.82m/s

6 0

3 years ago

A woman and her dog are out for a morning run to the river, which is located 4.0 KM away. The woman runs at 2.5 M/S in a straigh

VLD [36.1K]

River shore is located at distance

$d = 4 km$

speed of the woman is given as

$v_1 = 2.5 m/s$

now the time taken by the woman to cover the distance is

$t = \frac{d}{v}$

$t = \frac{4000}{2.5} = 1600 s$

for the same time interval the dog will run to and fro with speed 4.5 m/s

so the total distance moved by the dog is given by

$d = v* t$

$d = 4.5 * 1600$

$d = 7200 m$

<em>so the total distance that dog will move is 7200 m or 7.2 km</em>

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4 years ago

A typical student listening attentively to a physics lecture has a heat output of 100 w . how much heat energy does a class of 1

nexus9112 [7]

Since each student emits 100 W, so 170 students will emit:

total heat = 100 W * 170 = 17,000 W

Convert minutes to seconds:

time = 50 min * (60 s / min) = 3000 s

The energy is therefore:

E = 17,000 W * 3000 s

<span>E = 51 x 10^6 J = 51 MJ</span>

7 0

3 years ago