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3 years ago

Is the net force on an object moving with uniform velocity zero or not zero?

Physics

1 answer:

NikAS [45]3 years ago

3 0

Answer:

Zero

Explanation:

The net force acting on an object moving with uniform velocity is zero. This is an accordance with the Newton's first law of motion.

Newton's first law of motion states that a body will continue in its state of rest or uniform motion unless it is acted upon by an external force.

Since this body is moving with uniform motion, it is not accelerating. When a body is acceleration, the net force on it is not zero.

But this one is moving with uniform motion. The net force on the body is balanced and zero.

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Shelley is in an elevator that is traveling downward and slowing down at a rate of

liraira [26]

Answer:

N = 648.55[N]

Explanation:

To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.

∑F = m*a

where:

∑F = Forces applied [N]

m = mass = 73.2 [kg]

a = acceleration = 0.950 [m/s²]

Let's assume the direction of the upward forces as positive, just as if the movement of the box is upward the acceleration will be positive.

By performing a summation of forces on the vertical axis we obtain all the required forces and other magnitudes to be determined.

$-m*g + N = -m*a\\$

where:

g = gravity acceleration = 9.81 [m/s²]

N = normal force (or weight) measured by the scale = 83.4 [N]

Now replacing:

$-(73.2*9.81)+N=-73.2*0.950\\-718.092+N=-69.54\\N = -69.54+718.092\\N = 648.55[N]$

The acceleration has a negative sign, this means that the elevator is descending at that very moment.

8 0

3 years ago

A moon with a mass of 6.0 x 10 kg orbits about a planet with a mass of 5.0x 10^24 kg. They are 4.0 x 10^8 meters apart What is t

allochka39001 [22]

The gravitational force between them is <em>1.25 x 10^20 Newtons.</em>

(I think you must have typed the mass of the moon wrong.

It must be 6.0 x 10^22 kg.)

4 0

4 years ago

When a spinning star shrinks in radius, it speeds up. Which of the following statements explains this phenomenon?

Sever21 [200]

Answer:

B.)Angular momentum is always conserved

Explanation:

Angular momentum is given by:

$L=mvr$

where

m is the mass of the object

v is its speed

r is the distance between the object and the centre of its circular trajectory

In absence of external torques, angular momentum is always conserved. That means that for the spinning star, if its radius r decreases (because it shrinks), in order for L (the angular momentum) to be conserved, the speed (v) must increases, therefore the spinning star speeds up.

So, the correct choice is

B.)Angular momentum is always conserved

4 0

3 years ago

You need to get to class, 200 meters away, and you can only walk in the hallways at about 1.5 m/s. (if you run any faster, you’l

Pani-rosa [81]

200/1.5 = 133.33 seconds.

= approximately 2 mins and 13 secs.

6 0

4 years ago

Read 2 more answers

A hydrogen atom in a galaxy moving with a speed of 6.65×106 m/???? away from the Earth emits light with a wavelength of 5.13×10−

Mumz [18]

Answer:

The observed wavelength on Earth from that hydrogen atom is $5.24\times 10^{-7}\ m$ .

Explanation:

Given that,

The actual wavelength of the hydrogen atom, $\lambda_a=5.13\times 10^{-7}\ m$

A hydrogen atom in a galaxy moving with a speed of, $v=6.65\times 10^6\ m/s$

We need to find the observed wavelength on Earth from that hydrogen atom. The speed of galaxy is given by :

$v=c\times \dfrac{\lambda_o-\lambda_a}{\lambda_a}$

$\lambda_o$ is the observed wavelength

$\lambda_o=\dfrac{v\lambda_a}{c}+\lambda_a\\\\\lambda_o=\dfrac{6.65\times 10^6\times 5.13\times 10^{-7}}{3\times 10^8}+5.13\times 10^{-7}\\\\\lambda_o=5.24\times 10^{-7}\ m$

So, the observed wavelength on Earth from that hydrogen atom is $5.24\times 10^{-7}\ m$ . Hence, this is the required solution.

8 0

3 years ago