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2 years ago

When is the net force on an object equal to zero?

2 answers:

4 0

There are all kinds of conditions that could bring that about.

1. The most common one is friction. An object is moving that it is not accelerating. That means the frictional force is equal to the force causing motion.

2. The downward gravitational force is being negated by a rope suspending an object. The upward pull by the rope cancels the downward pull of gravity.

3. The rules of the game prohibit motion. A ballplayer would be stupid to leave second base while the pitcher has the ball in his hand (a physics joke. Please ignore).

4. A normal force upwards by the earth's surface is balanced by the weight of an object laying on the ground.

5. Speaking of baseball, there is no acceleration in the horizontal direction, so the net force on the ball horizontally is 0.

6. An elastic band held and aimed horizontally. The force of the elastic to launch a spitball vs the hand holding the elastic back waiting for the best time to let the spitball go.

That should get you going.

Rufina [12.5K]2 years ago

3 0

When ALL the forces are equal, or in general when forces in the opposite direction are equal

so we can have newton example:

10 newtons X -10 newtons

netforce = 0 newtons

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An object at rest does not _____ and an object in motion does not _____, unless an _____ force acts upon it

mel-nik [20]

Answer:

An object at rest does not move and an object in motion does not change its velocity, unless an external force acts upon it

Explanation:

This statement is also known as Newton's first law, or law of inertia.

It states that the state of motion of an object can be changed only if there is an external force (different from zero) acting on it: therefore

- If an object is at rest, it will remain at rest if there is no force acting on it

- If an object is moving, it will continue moving at constant velocity if there is no force acting on it

This phenomenon can be also understood by looking at Newton's second law:

F = ma

where

F is the net force on an object

m is the mass

a is the acceleration

If the net force is zero, F = 0, the acceleration of the object is also zero, a = 0: therefore, the velocity of the object does not change, and it will continue moving at the same velocity (which can be zero, if the object was at rest).

5 0

2 years ago

Question 3 of 32

Scorpion4ik [409]

Answer:

the clown can be put on a sealion and the other clown can hold a lot of peole he help a clown that was tall and heivy

Explanation:

3 0

2 years ago

The mass of earth 6*10^24kg and radius is 400kg Now find the value of acceleration due to gravity when a object is 3600km from t

vlada-n [284]

I don’t worry wewwwww it is a good time to get it done lol lol i don’t worry about it lol lol i lol

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2 years ago

2. a) A disc rotates about its axis at speed 25 revolutions per minute and takes 15 s to stop. Calculate the

ASHA 777 [7]

The statement shows a case of rotational motion, in which the disc decelerates at constant rate.

i) The angular acceleration of the disc ( $\alpha$ ), in revolutions per square second, is found by the following kinematic formula:

$\alpha = \frac{\omega_{f}-\omega_{o}}{t}$ (1)

Where:

$\omega_{o}$ - Initial angular speed, in revolutions per second.
$\omega_{f}$ - Final angular speed, in revolutions per second.
$t$ - Time, in seconds.

If we know that $\omega_{o} = \frac{5}{12}\,\frac{rev}{s}$ , $\omega_{f} = 0\,\frac{rev}{s}$ y $t = 15\,s$ , then the angular acceleration of the disc is:

$\alpha = \frac{0\,\frac{rev}{s}-\frac{5}{12}\,\frac{rev}{s}}{15\,s}$

$\alpha = -\frac{1}{36}\,\frac{rev}{s^{2}}$

The angular acceleration of the disc is $\frac{1}{36}$ radians per square second.

ii) The number of rotations that the disk makes before it stops ( $\Delta \theta$ ), in revolutions, is determined by the following formula:

$\Delta \theta = \frac{\omega_{f}^{2}-\omega_{o}^{2}}{2\cdot \alpha}$ (2)

If we know that $\omega_{o} = \frac{5}{12}\,\frac{rev}{s}$ , $\omega_{f} = 0\,\frac{rev}{s}$ y $\alpha = -\frac{1}{36}\,\frac{rev}{s^{2}}$ , then the number of rotations done by the disc is:

$\Delta \theta = 3.125\,rev$

The disc makes 3.125 revolutions before it stops.

We kindly invite to check this question on rotational motion: brainly.com/question/23933120

6 0

2 years ago

When reaching a boundary between two media (1 and 2), an incident ray is partially reflected and partially refracted. The ray is

podryga [215]

Answer: critical angle, sin^-1 (n2/n1)

Explanation: the angle of incidence at which the retracted ray makes an angle of 90° with the normal is known as the critical angle.

Snell's law defined refraction mathematically as shown below

n1 sin θi = n2 sin θr

n1 = refractive index of the first medium

n2 = refractive index of the second medium

θi = angle of incidence

θr = angle of refraction

When the refrafted ray is perpendicular to the normal, the angle of refraction (θr) is 90° hence making the angle of incidence (θi) the critical angle θc

By substituting these conditions into the Snell's law, we have that

n1 sin θc = n2 sin 90

According to trigonometry, the value of sin 90 is 1, hence we have that

n1 sin θc =n2

sin θc = n2/n1

θc = sin^-1 (n2/n1)

3 0

2 years ago