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3 years ago

Two steel blocks rest on a frictionless, horizontal surface. Block X has a mass of

Physics

1 answer:

stepan [7]3 years ago

3 0

Before you jump into this, you have to stand back, look at it, and decide what's going to happen.

You're pulling on some things that rest on a frictionless surface, so they have to start moving. In fact, they're going to accelerate.

Now, I want you to consider for just a second: What would happen if
the two blocks were glued together ? Then, you'd be pulling on a single
18-kg block, with 36N of force, and it would accelerate to the right at
[ A = F/M ] = 36/18 = 2 m/s² .

The actual situation is no different. The string between them has no weight,
and it's tight, and there are no other forces on the blocks, so the whole combination ... both blocks ... is still going to accelerate to the right at 2 m/s² .

OK. Now, let's look at the individual blocks:

The one in the back ... the 12 kg. It's accelerating at 2 m/s² to the right,
so the force on it must be [ F = M A ] = 12 x 2 = 24 N to the right. Where
does that force come from ? It's the tension in the string between them.

The one in the front ... the 6-kg.
It has 36 N pulling it to the right, and 24 N of string tension pulling it to the left.
The net force on this block is (26 - 24) = 12N to the right.
Its acceleration is [ A = F/M ] = 12/6 = 2m/s² to the right.

Well, whaddaya know ! Both blocks accelerate at the same rate, in the
same direction, just as if they were glued together, and the string between
them remains tight, with 24N of tension in it.

With this description, you can handle the FBD on your own, I'm sure.

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The law of reflection states that if the angle of incidence is 81 degrees, the angle of reflection is ___ degrees.

lilavasa [31]

81°.

The law of reflection states that the angle of incidence is equal to the angle of reflection.

6 0

3 years ago

The dial of a scale looks like this: 00.0kg. A physicist placed a spring on it. The dial read 00.6kg. He then placed a metal cha

saveliy_v [14]

Answer:

d. The scale's resolution is too low to read the change in mass

Explanation:

If we want to find the change in energy of the spring, we will have to use the Hooke's Law. Hooke's Law states that:

F = kx

since,

w = Fd

dw = Fdx

integrating and using value of F, we get:

ΔE = (0.5)kx²

where,

ΔE = Energy added to spring

k = spring constant

x = displacement

The spring constant is typically in range of 4900 to 29400 N/m.

So if we take the extreme case of 29400 N/m and lets say we assume an unusually, extreme case of 1 m compression, we get the value of energy added to be:

ΔE = (0.5)(29400 N/m)(1 m)²

ΔE = 1.47 x 10⁴ J

Now, if we convert this energy to mass from Einstein's equation, we get:

ΔE = Δmc²

Δm = ΔE/c²

Δm = (1.47 x 10⁴ J)/(3 x 10⁸ m/s)²

Δm = 4.9 x 10⁻¹³ kg

As, you can see from the answer that even for the most extreme cases the value of mass associated with the additional energy is of very low magnitude.

Since, the scale only gives the mass value upto 1 decimal place.

Thus, it can not determine such a small change. So, the correct option is:

d. The scale's resolution is too low to read the change in mass

8 0

3 years ago

46 points :)

IgorC [24]

Answer:

Its is dividing by 2

Explanation:

It starts with 100 them it goes to 50, 25, 12.5 so its a cycle of dividing by 2

3 0

3 years ago

Read 2 more answers

You throw a balloon that floats in the air with a velocity of 2 m / s south . If the wind speed is 5 m / s west , how far south

zvonat [6]

Answer:

The distance traveled by the balloon is 10.77 m

Explanation:

velocity of the ball, $v_b$ = 2 m/s south

velocity of the air, $v_a$ = 5 m/s west

To determine the distance the balloon will travel after 2 seconds, first determine the resultant velocity of the balloon.

| 2m/s

↓

5m/s ←------------------

the two velocities forms a right angled triangle and the resultant will be the hypotenuses side of the triangle.

R² = 5² + 2²

R² = 29

R = √29

R = 5.385 m/s

The distance traveled by the balloon is calculated as;

d = R x t

where;

t is time of the motion = 2 seconds

d = 5.385 x 2

d = 10.77 m

Therefore, the distance traveled by the balloon is 10.77 m.

4 0

3 years ago

When water waves meet, they can combine to form new waves. In constructive waves, a ________ amplitude wave is formed. In destru

Sever21 [200]

Answer:

In constructive waves, a greater amplitude wave is formed. In destructive waves, a wave with a smaller amplitude is formed. (option A)

Explanation:

Interference is called the superposition or sum of two or more waves. Depending mainly on the wavelengths, amplitudes and the relative distance between them, there are two types of interference: constructive or destructive.

Constructive interference occurs when there are two waves of identical or similar frequency (both have motions equal to an even number of similar wavelengths) and overlap the peak of one with the peak of the other. These effects add together and make a wave of greater amplitude. All of this is possible because the waves were in the same phase in the beginning (in the same position).

Destructive interference occurs in the opposite case to constructive. When the crest of one wave overlaps the valley of the other, they cancel out since they are in different phases when they overlap (they were in different positions). That is, as in the case of constructive waves they were added, in the case of destructive waves they cancel out (subtract).

So, In constructive waves, a greater amplitude wave is formed. In destructive waves, a wave with a smaller amplitude is formed.

3 0

3 years ago