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A 4 kg object moving to the left collides with and sticks to a 3 kg object moving to the right. Which of the following is true o

madam [21]

Answer:

D. The motion cannot be determined without knowing the speeds of the objects before the collision.

Explanation:

This question is tricky! We know the object moving to the left has a greater mass than the one moving to the right. We'd assume they would move to the left because the leftwards object has a greater mass, right?

Not. So. Fast.

We can solve for the objects' final velocity using the formula for momentum, m₁v₁ + m₂v₂ = (m₁ + m₂)v .

Now here's where the trap is sprung: we don't think about the equation. This shows that the final velocity of the objects and the direction depends on both the mass of the objects and their initial velocity.

Basically, what if the 3 kg object is moving at 1 m/s and the 4 kg object is moving at –0.5 m/s? The objects would move to the right after the collision!

Do we know the velocity of these objects? No, right?

That means we can't determine the direction of their motion unless we know their initial, pre-collision velocity. This question is tricky because we look at the 4 kg vs. 3 kg and automatically assume the 4 kg object would dictate the direction of motion. That's not true. It depends on velocity as well.

I hope this helps you! Have a great day!

4 0

3 years ago

The tub of a washer goes into its spin-dry cycle, starting from rest and reaching an angular speed of 2.0 rev/s in 10.0 s. At th

Arte-miy333 [17]

Answer:

22 revolutions

Explanation:

2 rev/s = 2*(2π rad/rev) = 12.57 rad/s

The angular acceleration when it starting

$\alpha_a = \frac{\Delta \omega}{\Delta t} = \frac{12.57}{10} = 1.257 rad/s^2$

The angular acceleration when it stopping:

$\alpha_o = \frac{\Delta \omega}{\Delta t} = \frac{-12.57}{12} = -1.05 rad/s^2$

The angular distance it covers when starting from rest:

$\omega^2 - 0^2 = 2\alpha_a\theta_a$

$\theta_a = \frac{\omega^2}{2\alpha_a} = \frac{12.57^2}{2*1.257} = 62.8 rad$

The angular distance it covers when coming to complete stop:

$0 - \omega^2 = 2\alpha_o\theta_o$

$\theta_o = \frac{-\omega^2}{2\alpha_o} = \frac{-12.57^2}{2*(-1.05)} = 75.4 rad$

So the total angular distance it covers within 22 s is 62.8 + 75.4 = 138.23 rad or 138.23 / (2π) = 22 revolutions

6 0

3 years ago

Please help with this :(

Rainbow [258]

Answer:

I don't really know but i have an idea

Explanation:

so acceleration means: increase in the rate or speed of something.

so just a head start.

your welcome!!

3 0

3 years ago

If hydrogen and helium are the most abundant elements in the unoverse , then why are living organisms composed primarily of carb

Mumz [18]

Answer:

Most of materia isnt life.

Explanation:

The living organisms (life) aren't the most abundant thing in universe.

Hydrogen and helium are present in everywhere, but life isn't.

There is no reason to think because we have a lot of a thing, the life must be made for this thing.

The organic life just can exists because some mysterious properties about carbon, that is the basic foundation of life, carbon is a special element, why? We don't know, actually, it's a huge problem for science discover why the carbon can makes life be possible and other elements can't. But we know is this element that makes life possible.

So, note there isn't relation about the quantity of a material in Universe and the life constituition. In addition, look around, organic materials are very rare in Universe, Earth is one in lots of places and in most of this places there isn't sign of life.

Even in Earth the life looks abundant, in Universe it isn't, the same way in Universe the Hydrogen and Helium are abudant, in Earth isn't soo.

3 0

3 years ago

"My distance to the center of the earth is about 4000 miles when I am on the surface. If I go to a height of 8000 miles above th

lord [1]

Given,

Distance from the surface to the center of the earth, d=4000 miles

Distance from the center to you at a height of 8000 miles, a= 8000+4000=12000 miles

The gravitational force acting on a person at the surface is equal to his weight.

From Newton's Universal Law of Gravitation, the gravitational force is

$F=\frac{G\times M\times m}{r^2}$

Where G is the gravitational constant, M is the mass of the earth, m is the mass of the object/person, r is the distance between the center of the earth and the object/person

At the surface, this force is equal to the weight of the person, W=mg

i.e.