Physics Questions on Leverage Physics Physics questions about levers should be solved in detail

Solution: From the meaning of the question: l1 l2=2 1, l1=2l2 is obtained from f1 l1=f2 l2: the force acting on the b-terminal is: f2=(f1 l1) l2=(

The gravitational force of the iron ball is: g=mg=5

The buoyancy force experienced by the iron ball is: f float = g - f 2 =

The iron ball is submerged in water.

The actual volume of the iron ball is v = v row = f float ( water g) = 5kg The volume of the solid iron ball is: v solid = m = 5 v v solid The iron ball is hollow.

Do your homework yourself.

f1*s1=f2*s2

f2=ffloat=g-f2=5*

V-ball = F float (density of water * g) =

1 1000 cubic metres.

Ball density = 5 (1 1000) = 5 * 10 3kg m 3 "So the iron ball is hollow.

The buoyancy of the water +

Buoyancy of water = 5*

3 1000 = cubic meters.

If the iron ball is solid, the cubic meter weighs kilograms.

So the ball is hollow,

From the force analysis and the principle of the force on the bar, it can be obtained: assuming g = , g - f = 2 * gravity of the iron ball minus buoyancy) f = water density * g * volume of the iron ball. g=m*g。

Water density and g = known to find the volume of iron balls. Then the density of the iron ball is obtained from the mass of the iron ball and the volume of the iron ball, and the density of the iron ball is compared with the density of the iron ball to know whether the iron ball is solid or hollow.

Due to the lack of conditions given, the specific solution is still up to you.

When the fulcrum is in.

When striking at a distance of 30cm from the rough end, the wooden stick can maintain horizontal balance. bai indicates that this point is the position of the center of gravity of the stick.

The fulcrum moves to off.

At 50 cm at the thick end, in order to restore the horizontal balance of the stick, it is necessary to hang a suitable weight at the thin end.

Let the gravitational force of this weight be g

g*40cm=g=

Solution: Let the gravity of this weight be g, and when the fulcrum is 30cm away from the thick end, the wooden stick can maintain horizontal balance. This point is where the center of gravity of the stick is located. When the fulcrum is moved to 50 cm from the thick end, in order to restore the horizontal balance of the stick, it is necessary to hang a suitable weight at the thin end).

g*40cm= (according to the lever balance column) The result is .

g = so at which end the object should be hung.

The moment is generated by friction, and the arm is the radius r, therefore.

f (Mo) = 1000

The pressure at point b f(b) = f (motor) u = 10000n according to the principle of lever f * oa = f (b) * ob

f=10000*

Sorry, in addition to f(b)*ob, there should be a drag moment where the friction of the wheel to the right of the lever is multiplied by d

So there is f*oa=f(b)*ob+f(mo)*d to get f=(10000*

It's supposed to be this, I'm really sorry just now.

Answer: 20n

Solution: According to the positive condition of the leverage equilibrium:

f1×l1＝f2×l2

Got: Guess f1 f2 l2 l1 50

I don't know what to ask.

1. The principle of balance by leverage: f1l1=f2l2

i.e. 500 2 900*l2

Dad should stand at the fulcrum of the stupid void as follows: l2=10 9 m2, f1l1=f2l2

f1v1t = f2v2t

i.e. 500 dad speed cautious liquid v2 = 2 9 m with filial piety s

1: Set to x, so the balance with leverage is 200*x=300*(,x=

2: The center position is unchanged, the length of the rod is L, the center of gravity is L1 from the end of the first lift, there is 80 * (L-L1) = 50 * L1, and when the other end is lifted, there is 80 * L1 = X * (L-L1), L is regarded as known, substituted it, not counted, it should be 110, such problems are the sum of the force used at both ends is twice the force of gravity.

1、l1*f1=l2*f2

Because l1+l2= f1=300n, f2=200n, the solution gives l1= l2=

2. I don't understand the topic, does it mean that he removed the previous force of 50N and then slowly lifted the force used at the other end?

2.I think upstairs understands correctly.

Drawing: Wooden stick ab, g is the center of gravity, l1=ga, l2=ab, l3=gb, g=f1).

According to l2 l1=f1 f2=80 50=8 5l3=l2-l1

So l3 l2=3 8

f3=(l3/l2 )*f1=3/8*80=30n

Answer: c

Reason: The force arm of point A tension force is equal to ao, and the force arm of point B tension force F is less than Bo, that is, the force arm of F is small, if the lever is balanced, according to the lever balance conditions: power power arm = resistance The resistance arm knows, the force arm is small, and the force is large.