Two physics problems, thank you, help solve them!! Rush Rush

Because it is to ask the pressure of the bottom of the container to the ground, so the container is regarded as a whole, regardless of the shape, anyway, some mass is pressed on the bottom area, if Ma is greater than MB, then the total mass A is greater than B, then Pa is greater than Pb, the same can be obtained B, C is wrong. In addition, if you ask the pressure of the liquid on the container, use the formula p = p (density) g (acceleration due to gravity) h (liquid height).

It is the release of heat to the surroundings, if it absorbs heat, the answer is 16 degrees, there is no such answer, and the warm water becomes cooler to match the reality. From the conservation of energy, the heat absorption and exothermia of the system are equal, let the final temperature be t, the heat of the system is multiplied by (20-t), and the heat absorption of the system (t-15)*2*, and the two are equal to t=degrees.

I'm a junior high school student with little knowledge, so I don't know if I can help you, but I'll help you out.

The first question selects C analysis: when the bottom area is certain and the cup quality is certain, there is no need to consider this problem (Note: container A is a conical open bottle, and bottle B is a cylindrical bottle with a flat liquid level). So MA's second question is out of my scope.

The first question is B C

Useful, the water will eventually be equal to room temperature, however, is after a long time.

1.From the meaning of the title, it can be seen that both the time and the time ball are in the ascending stage, then.

The displacement of the rod within this is.

The displacement v0 (t2-t1) inside the pellet

For small balls, the acceleration is -g).

Analysis: The upper end of the club goes down, and the ball rises, and you can also know that the distance of the ball rising is the distance between the lower end of the rod in the initial position and the upper end of the club in the last position.

Therefore, v0=10m s, the height of the ceiling can be calculated from the first encounter between the two. That is, the ceiling height = the length of the pole + the distance of the rod falling + the distance of the ball rising = 1+

2.(1) The boat should travel 200 4 = 50 seconds 50 seconds and the water flow is 100 meters, so the direction of the boat should be 100 meters upstream at the opposite shore (2) The angle between the boat's sailing speed and the upstream river bank is 30 degrees t=d v=200 2 roots 3=100 roots 3 seconds.

1. t= s t = s

square) + square +1m=h ·· square) + square =h ·· The answer can be solved by the system of simultaneous equations.

2.Deviate 30 degrees upstream. v = 2 roots 3 m s t = d v = 200 (2 roots 3) = 100 roots 3 3

The bow of the boat is facing the river bank and the path is 45° downstream. t=d/v=200/4=50 s

Question 1, 10 meters|seconds, 6 meters The second question did not learn.

Solution: According to the principle of force synthesis, it is known that the magnitude of the resultant force is (12 2 + 16 2) = 20n under the root number

So the magnitude of the acceleration a of the object is 20n

So the magnitude of acceleration is 8m s 2

That's it!

This is from the textbook example.

It's not hard to look into this.

The classmate who sent the answer, this is not good, and it can't help the landlord.

And acceleration has to be directional.

Loudness tone.

The size and amplitude of the timbre, [think for yourself this example].

Chicks, amplitude, pigs, frequency.

Looks like you and I are in the same textbook, shake hands!

1.1 Loudness.

2. Pitch high. 3. Good timbre.

2. Strength Amplitude For example, the greater the amplitude of the vibration of the drum surface when beating the drum, the greater the loudness, and the 3. Chick amplitude Pig frequency.

Deafening refers to the sound of sound:

Crisp as a silver bell refers to the high pitch of the sound

Pleasant refers to the sound of sound.

Loudness indicates the amplitude of the sound: the loudness of the sound is the same as the vibration of the sound source, and the loudness of the chick cry is small; The amplitude is smaller.

The low pitch of the pig's cry indicates that the vibration frequency of the site where it occurs is low.

1.Loudness; Tone; Timbre;

2.Size; Amplitude; Summer hand-cranked fan.

3.Chick; Amplitude; Pig; Frequency.

Total work = (50 + 16) x 10x (3x2) = 3960 joules useful work = 15x10x (3x2) = 900 joules useful work power = 900 30 = 30 watts.

Mechanical efficiency = 900 3960 =

Total work: mgh = (50 + 15 + 1) * 3 * 2 * 10

Mechanical efficiency: 15 (50+15+1).

Active power: 15*10*3*2 30

None of this? I've forgotten the formula, it's been too long. But I know it's very simple. What kind of law of conservation of energy to use, forget it, I don't think about it, I guess I won't need it in this life.

Solution: 1) The heat absorbed by the water obtained by Q absorbs c water * m * (t2 t1) is.

q *1 *(85 25) 10 5 joules.

2) The electrical energy consumed by the induction cooker for operation is:

e (150 2000) kWh (150 2000) * 1000 * 3600 joules *10 5 joules.

3) The actual power of the induction cooker is:

P real e t *10 5 joules min *10 5 joules 150 seconds 1800 watts.

1) The ascent and fall times are equal. So the free fall time is 4s, v=gt=10 4=40ms.

ek=1/2×

ep=02) the highest point velocity of the conservation of mechanical energy is 0, ek=0ep=40j

3) When the gravitational potential energy is half of the original in the middle position, the reduced gravitational potential energy is converted into kinetic energy. ek=ep=40/2=20j

From the time it is thrown to the point of landing, it takes 8 seconds, and the ascent and descent times are 4 seconds each.

The initial velocity is v0=gt=10x4=40m s

The kinetic energy when thrown is ek=mv0 2=

When the potential energy is 0 and the highest point of the highest point can be known according to the law of conservation of mechanical energy (or calculate the maximum height reached, and then calculate EP=MGH), the gravitational potential energy is 160J and the kinetic energy is zero.

When reaching half the height, the gravitational potential energy is halved and is 80j, then the kinetic energy is 160-80=80j.

Throwing vertically from the ground, regardless of resistance, you can see the ascent and descent as the opposite process.

One is to convert kinetic energy into potential energy, and the other is to convert potential energy into kinetic energy, and at the highest point, the velocity is zero, the kinetic energy is zero, and the potential energy is maximum. The acceleration of the whole process remains unchanged, the time is 4s respectively, the maximum velocity value is v=at=10*4=40, the kinetic energy is the largest when thrown, e=(m*v*v) 2, and the potential energy is zero. At the highest point, the potential energy is the largest, which is the maximum kinetic energy just now, and the kinetic energy is zero at this time.

The maximum height s=a*t*t 2=10*4*4 2=80m, the ascent is 40 meters, the time is 2 times the root number 2, the speed is 20 times the root number 2, the kinetic energy e=(m*v*v) 2, the potential energy is the maximum kinetic energy minus the kinetic energy at this time.