An easy science question Urgently, thank you 20

The coordinates of Beijing urban area are: north latitude, east longitude 116 3”。

Shenzhen longitude 113°46 to 114°37 east longitude, 22°27 to 22°52 north latitude

Beijing: East longitude 116°28 North latitude 39°54.

Shenzhen: 113°46 east longitude'～114°37', 22°27 N'～22°52'

Resistance f=100 n

If it moves at a constant speed, the engine traction force is f=100N

Then the power required to drive the battery car at a constant speed of 400m w=100 400=40000 J The output power of the battery to the car p=24 50 w

Time t=w p= s

f resistance = 1000*

Constant velocity: f resistance = f traction force.

Power p = f traction * v

Power p = 80% * ui = efficiency 80% means 80% for traction work) p = f traction force * v = 960

v=t=s/v=400/

During the live broadcast of Xiao Li and Xiao Ming's ** Olympic gymnastics competition, it was found that athletes repeatedly rubbed a powder on their hands before the horizontal bar competition. The two wondered, "What's the point of doing that?"

Xiaoli believes that this is to reduce friction and help athletes complete the loop action on the horizontal bar; Xiao Ming thinks the opposite, he thinks this is done to increase friction and prevent athletes from getting out of the horizontal bar. The two expressed their opinions and argued fiercely.

Obviously, the above explanations of Xiao Li and Xiao Ming are their personal opinions. From a scientific point of view, when people disagree on their opinions, whether those opinions or perceptions are correct or not requires the search for evidence to prove it. So, how do they go about gathering evidence?

I would like to ask you to give them two sound suggestions.

Look up information on the Internet and ask your science teacher

The original question was found:

Survey Interviews Data Inquiry.

Dial: There are many ways to collect evidence, such as experiments**, visits, etc. The main links of science** are asking questions, conjectures and hypotheses, making plans and designing experiments, conducting experiments and collecting evidence, analyzing and demonstrating, evaluating and communicating and cooperating. ）

Buy some powder for experiments;

Ask local athletes or look up information online;

Personal opinion, it doesn't seem to be a very good answer either).

Explained with the theory of relativity.

Grandpa said that running 2km is relative to the treadmill.

The reference he chose was the treadmill, and Xiao Ming's statement was relative to the surrounding environment (floor, walls, ceiling, etc.).

The reference material chosen is the floor, wall, ceiling, etc.

Motion is absolute, rest is relative, there is no such thing as absolute rest!!

Trains can't run on the road.

Let's just take 250 kilometers per hour and change it to meters per second, and divide it by 500 meters by speed.

One hour is equal to 360 seconds, 360 divided by 250 is equal to the bullet train travels kilometers per second, so it only takes seconds to reach the pedestrian.