Question 8. Ask for answers. Senior 1 Physics

Aren't you already marked in red with a C?

The earth rotates from west to east because of gravity, all objects on the earth have relative inertia. It's about moving with the earth. For example, if you throw a tennis ball in a train car, the tennis ball will still run in the direction you still have, instead of flying directly to the back of the train.

But if suddenly the earth no longer exerts force on the object, the object will no longer be stationary with respect to the earth. Then the earth turns east, and the object will of course move west relative to you. It's like a car driving on the highway, and the trees on both sides are running backwards.

But where this question is not rigorous is upwards and westwards. If an object is not gravitationally attracted by the Earth, it will be affected by other gravitational fields in space, such as the Sun, the Moon, Mars, Venus, etc.

So it is difficult to say in which direction these resultant forces are. It is not necessarily that without the gravitational pull of the earth, it will fly directly to the surface of the earth.

Personally, I think that this question can be understood in this way: because the earth has an orbit around the sun, and you are standing on the equator, then when the gravitational attraction is suddenly lost, the apple will form a tangent shape similar to the equator because the earth turns westward, and at the same time, because the revolution and the equator form a tangent shape, and because the orbit is elliptical, it will give the apple an upward component (here it is assumed that other gravitational fields in the universe have little influence on the apple, which is ignored).

So choose C

The force on the left and right eggs is the same, but when the collision occurs, the egg in the right hand stops, and the egg liquid will move to the left, resulting in an increase in the density of the right-hand egg on the collision surface, while the density of the collision surface of the left-handed egg remains unchanged. The degree of plastic deformation of the object is related to the density, the greater the density, the smaller the plastic deformation under the action of the same force. Therefore, the left-handed egg will break first.

The earth turns from west to east, and after there is no gravity, you still turn from west to east, and the apple does not move, you know?

Suppose the Earth has no gravitational pull on a sudden apple, then the apple will fly out of the tangent direction of the original linear velocity at the Earth's equator, and you will still be at relative rest with the Earth at the same velocity. But you can imagine that the apple is in that position, because you're doing arc motion, he's doing linear motion, and you all have the same rate. So choose C

Consider the rotation of the Earth....When you hold it, the apple already has a speed from east to west....But I think I choose D

You can take a look at Newton's first law in the 8th grade physics textbook, and the content is that the object maintains its original motion when it is not subjected to force, and moves eastward when it is not gravitational, and you move in a circle on the earth. I choose D

I think we should choose C, after losing gravity, the apple will do centrifugal motion, so it will go up, and its speed will not change after going up, but the radius of doing circular motion increases, so the angular velocity decreases, and the earth is rotating from west to east, so it will be slower than you and westward.

8 Answer 1:2 1: Socks noisy 2

It is derived from the theorem of the action and the fighting servant.

mgs=0-ek

s=ek mg s1:s2=m2:m1=1:2s=1 2at2 a= g t=(2s g) 1 2t1:t2= s1: pinonly s2=1: 2

When balancing the friction force, put one end of the board too high, so that when there is no tension, the trolley will start to move under the action of the combined force of gravity (mgsin) and friction (mgcos) ("the downward force of gravity is greater than the friction force"). The tensile force f=0 and the acceleration is:

a=（gsinθ-gcosθ)>0

From the four plots, only c is f=0 and a is greater than 0

f-f=ma

a=f/m-f/m

f m does not change, f becomes 4f, and a should be greater than 4a. I choose a CD

Because the resistance of the water is proportional to the square of the speed of the boat.

So, if the resistance is f when the velocity is v, then the resistance is 9f when the velocity is 3v.

p=fv=fv, so when the speed is 3v, p'=27p

Let f=kv 2

When driving at V, the traction force is equal to F p=fv=kv 3

Traction is equal to f' p when driving at 3V'=f'*3v=k(3v) 3=27kv 3=27p

The total distance is set to s

The total time is 2s 3v1+s 3v2

The average velocity is 1 (2 3v1+1 60)=28, and the equation can be solved.