A physics question is answered on its knees and gives 50 points

At maximum velocity, f=f=p=fv=p=vp=50000v, kinetic energy theorem wf= mv2 pt

So v = 30m s p = 15000000w at this time the traction force f = p v = 1500000n f = f f = ma a = 1m s2

It's not a place to do your homework, this question is relatively simple, turn the book yourself.

The velocity of the two balls A and B is the same, so that the mass of ball A is m and ball B is m', the radius of the cylinder is r. At the highest point, the ball armor can do a flat throwing motion, which means that gravity just provides centripetal force at this time, so there is.

mv^2/r=mg

i.e. v 2=gr

It can be obtained from the conservation of mechanical energy.

2m'gr-2mgr='v^2 ②

Lianli, yes.

m/m'=3/5

Hope it helps.

There is one thing I didn't take into account, so the previous answer is a bit problematic.

The height at which B descends is not 2r

It should be (2+1)r

So the formula should look like this.

/2+1)m'gr-2mgr='v 2 so m m'=（π+1）/5

Hope it helps.

Let the radius of the cylinder be r, and it can do the flat throwing motion, indicating that the motion speed of A satisfies mA v*v r=m Ag, the velocity on the rope is the same, and the velocity of B is the same as A, and 1 2(m A+m B) v*v=2(m B-m A) gr is obtained according to the conservation of mechanical energy

From this, the result should be 5 3 times, the idea is here, and the accurate result has to be calculated by yourself.

？Actually, the answer is a bit strange column, B is down, it has to be heavier, but the answer shows that B is lighter than A???

A piece of metal with a volume of 1*10--4m3,[1] if it is submerged in water, how much buoyancy will it experience? [2] If at this time the metal block is hung on the spring dynamometer.

, when submerged in water, what is the spring dynamometer?

High school competition questions. A little excitement is coming. There are also parentheses.

The parentheses mean that the rope off the ground is straight and straight, so that it is much simpler and there is no friction.

First, divide the rope infinitely (each small segment is lowercase, and the whole is uppercase), length x, mass m = (x x)m

For every increase in x height, it is equivalent to the length of the rope tail x to the height of f, with fx = mgh + (ek increase) (h from 0 to 1 m).

So the total work is fx=mg(h2)= so f=square=5+8=13 N, so (a) fhe= so a=8 (meters per square second) (two) f=ma2 a2=13 (meters per square second) (three) the force below the center is so t=ox.

The first question, I agree with the statement of the first floor, using the division method, but there is a little error in the calculation of the first floor, when calculating the mass, substitute, so a=16m s 2

The second question is the same as on the first floor.

For the third question, it is also the same as the first floor.

Buoyancy f= It can be seen that the buoyancy is proportional to the depth of the wooden block into the water, so the buoyancy f=2mg when fully immersed, and half to full immersion after immersion: w1=3 2mg*l 2. (F-L image method to find the area).

Immerse all the wood blocks to the bottom: W2 = 2 mg*l 2. The work done by buoyancy w=w1+w2

Slow immersion: It means that the whole process of the wooden block is in a state of equilibrium, so the work done by the thin rod is equal to the work done by buoyancy plus the work done by the gravity of the demolition of the Dan Jane wg=mgl.

Let the distance between ABs be 2s, the average speed of the car between ACs is V1=20KMH, and the time from A to C is T1, then T1=S V1

In the same way, the distance between CB is S, the average speed is V2=30KMH, and the time from C to B is T2, then T2=S V2

Then the average speed of the car between AB is V=2s (T1+T2), and the substitution is V=24km h

Basketball velocity before touching v= (v 2-2gh) Mingsheng Yu 8m s The force of the basketball on the ceiling is equal to the force of the ceiling on the basketball rolling FFT+MG 3 4mv-m(-v)=7 4mv=7kg*m sf=(7-5).

v^2-v0^2=2gh v^2-100=-2*10* v=8m/s v'=3 Sun Yetan4v=6m s is selected downward as the square, then Tong direction mv'Spine Sakura-mv=ft mgt 8)= 5) f= according to Newton's third law f'=f=

(1) -umgs=1/2mv^2-1/2mv^2

The first v is the desired speed, the second v is the speed of the start, it can also be written as v0, and the data is substituted to obtain v=3

2) h=gt 2 s=vt where v is the first problem, where s is the horizontal distance, bring in the data to get s=

Object gliding on a horizontal tabletop, ox two.

umg=ma

v^2=v0^2-2as

The velocity of the object as it leaves the edge of the tabletop v=

Leave the edge of the table and throw it flat.

h=(1/2)gt^2

x=vtThe distance between the object and the table is x=

Read page 132 of the ninth-grade physics book Specific heat capacity.

q=cm(t-t0)==

Actual consumption of electrical energy 90 1500

60 reduced to 18

The time required is t=12s

The displacement of the express train is s1=

The displacement of the truck is s2 = 219m

Will not collide. The shortest circuit distance is when the speed is 18.

s=1000+

I hope it can help you, and I wish you progress in learning, and don't forget to adopt!