What do you do when riding a bike up steep slopes? Briefly explain your reasons for doing so.

Accelerate as much as possible before going uphill, start the uphill at a maximum speed, and due to inertia, the bike will "try to" maintain its original motion and will go uphill at an average speed that will be relatively fast.

In general, it is like prostrate the body on the car, which can reduce air resistance, and at the same time, lower the center of gravity to make the system composed of people and vehicles more stable and less prone to falling. Well, that's how it should be.

The S-shape detours up.

When the work done is certain (the height is constant), according to w = fs, f decreases when s increases, that is, the effort is saved.

Summary. Kiss! Hello! We're happy to answer for you!

That's right. Because the angle between the slope and the ground is larger, the shorter the distance, the greater the steepness, and the more strenuous it feels.

When riding a bicycle to climb a hill, the greater the angle between the slope and the ground, the more difficult it is when it is a flat angle. Is that right?

Kiss! Hello! We're happy to answer for you! That's right, because the greater the slope-to-ground angle, the shorter the distance, the steeper the steepness, and the more strenuous it feels.

Extended information: From the perspective of work, slope, as an inclined plane model in physics, can play a role in saving labor, just like levers and pulleys. Taking the lever as an example, the length of the power arm is several times that of the resistance arm, which can achieve several times the labor-saving effect, and the same for the smooth inclined plane, the length of the inclined plane is several times the height, which can achieve several times the labor-saving effect.

That is to say, according to the principle of inclined plane, the smaller the slope or the longer the inclined plane, the more labor-saving the branch imitates. Why is it that the smaller the slope, the less effort? Because when an object is on an inclined plane, part of its gravity is borne by the inclined plane.

As can be seen from Figures 1 and 2, the gravity of the object is vertically downward, and the gravity can be decomposed into two components perpendicular to each other: one parallel to the inclined plane and the other perpendicular to the oblique surface. The component of the force perpendicular to the inclined plane is entirely borne by the inclined plane and no other force is required to act on it.

That is, the inclined plane can bear part of the gravitational force of the object, and the smaller the slope, the greater the gravitational force of the object that the inclined plane can bear. When the slope of the inclined plane is zero, the inclined plane becomes horizontal, and the force perpendicular to the inclined plane reaches the maximum value, which is equal to the full gravitational force of the object. When pushing an object upwards from the bottom of an inclined plane, two forces need to be overcome:

One is the component force parallel to the inclined downward, and the other is the object and oblique.

Of course, there is a difference, but actually riding a bike up a steep hill is a bit harder than riding a gentle hill, and you can get on the bike and try it. In principle, it is also easy to understand that the bicycle relies on inertia to maintain balance, that is, the bicycle must reach a certain speed, and it can ride smoothly due to inertia. When going uphill, because there is a certain initial speed, the bicycle has a certain kinetic energy, after going uphill, the bicycle is raised, and the kinetic energy is converted into potential energy.

On the contrary, the height rises quickly, the speed is smaller and faster, and in order to balance, you have to pedal harder, which is more difficult.

Solution: (1) Observing the diagram, it can be seen that from zero speed to zero speed is how much time he walked in total, a total of 20 minutes, and the highest point of the vertex is the maximum speed, so the maximum speed is 30 kilometers;

A: It took 20 minutes and his top speed was 30 km/h

2) As we know from the figure, when the broken line is flat, it means that the speed is constant, so it is: from 2 minutes to 6 minutes and from 16 minutes to 18 minutes;

A: From 2 to 6 and from 16 to 18, Xiao Ming rides at the same speed

3) The descent of the broken line is said to start climbing, and the end of the upward spiral of the broken line, so from the 6th minute Xiao Ming started to climb, and the climb was shared: 10-6=4 (minutes), when climbing to the top of the slope, Xiao Ming's speed was 5 kilometers;

Answer: From the 6th minute, Xiao Ming started to climb, the climb took 4 minutes, and when he climbed to the top of the slope, Xiao Ming's speed was 5 kilometers

4) The line starts to rise from 10 minutes, so it means that the descent is started, so the downhill time is: 12-10 = 2 (minutes), and the speed is 30 km/h

Answer: It takes 2 minutes for Xiao Ming to go downhill and the speed is 30 km/h

(1) 20 30 km per hour.

2) 2 to 6 16 to 18 (3) 6 to 10 8 5km per hour.

Fourth, think to yourself, I have the same test paper as you, I am also a sixth-grader, you have to pay attention, the upper is downhill, the downward is uphill, that is the speed, ok??

Hope it helps.

(1) Because the kinetic energy is related to the mass of the object and the driver, it is often necessary to pedal a few times before riding a bicycle uphill, that is, the mass of the person and the bicycle remains the same, but its speed becomes larger, so its kinetic energy becomes larger; At the same time, the gravitational potential energy is related to the mass and height of the object, so stepping up a few times can increase the speed, so that the car has a large enough kinetic energy before going uphill The car is in the process of going uphill, which is the process of converting kinetic energy into gravitational potential energy, so the greater the kinetic energy, the more it is converted into gravitational potential energy, so that the car is easier to reach the top of the slope

2) The original length of the spring is 10cm, and the tensile force of 5 Newtons is 12cm, that is, within the elastic limit, the spring will be subjected to a tensile force of 5N for every 2cm elongation, so the tensile force of the spring when it is elongated by 3cm is: f=5n

2cm×3cm=

So the answer is: speed; Height; Velocity; Kinetic energy; Move; Geopotential; Many;

Pedal a few times before going uphill, in order to get more speed, when the mass is the same, so that more kinetic energy will be obtained, when the vehicle goes uphill, there will be more kinetic energy converted into gravitational potential energy, the higher the bike will go, the easier the car will be uphill, regardless of friction and upward force

Therefore, choose B

Whether it is uphill or downhill or flat, the work done by cycling and pushing a bicycle should be about the same, why is it that in some cases it is labor-saving to ride a bicycle and in some cases to push a bicycle is labor-saving?

So in the final analysis, we must first figure out: what is the advantage of riding a bicycle compared with a cart?

The bicycle amplifies the travel through the transmission mechanism (consisting of pedals, gears, chains, etc.), which means that the distance of one meter of your foot on the pedal will allow you to move several meters. When riding a bike, a person's feet don't need to move as fast as they do when running, and this method is suitable for moving quickly when there is less resistance (the resistance of the rolling friction of the bicycle is generally less). To use an analogy, it's like using one of these levers:

You are very close to the fulcrum, and the load object is very far from the fulcrum. When the load and drag are small, you don't need to make a quick movement to accelerate the object very fast.

However, when the resistance is high, such leverage is not suitable - it is too strenuous. For example, when the uphill slope is steep. The resistance is amplified again through the transmission mechanism, and it is very difficult to pedal the pedal, so it is better to push the cart slowly. Unless you have a bike with a reduced itinerary and is specifically designed to ride uphill.

When traveling at a slow speed, it is not more convenient to ride a bicycle than a cart, because the feet are already moving slowly, and the advantage of amplifying the stroke is gone.

In addition, if the road is too rough, the bicycle will not be able to take advantage of the low rolling friction, and it will be difficult.

How do I feel like riding uphill is easier?

First of all, both processes increase the gravitational potential energy the same.

However, the work done by friction is not the same in the two processes.

Riding at a constant speed can be seen as friction doing work for constant force, and the positive pressure on the tires is caused by the mass of the bicycle and the mass of the human body.

If you walk up, the friction on the bicycle is smaller, but with the friction on the ground, it is difficult to say whether it is greater or smaller (the posture of walking, the speed of strides are affected).

Therefore, the work done by the two processes is not the same.

As for feeling tired, this is not directly related to doing work.

First of all, you can experience which is more tiring to do two push-ups normally or to do push-ups and hold down for 10 minutes, but theoretically you have done negative work.

In addition, we can be sure that the shifting bike is not very labor-saving (at least theoretically, the power does not change after shifting), but it is obvious that going up the same slope with different gears and the same speed (normal speed, too fast will involve the problem of fatigue caused by too fast cadence), and using a small crankset with a large cassette will be more labor-saving and feel more relaxed.

Here's a hint for you.

1. Conservation of energy.

Initial energy + work done by the person = work done by friction + last potential energy + last kinetic energy The work done by the person is equal to the traction force multiplied by the distance traveled.

2. The friction force is calculated according to 1 energy, and the friction force is multiplied by the distance + arrival is the potential energy obtained = initial energy (calculated by the column equation), and there is a triangular relationship between height and distance.

Cycling mainly relies on the strength of the legs, and all the work used is concentrated on the legs. The work used by the cart is almost distributed, and the work is relatively uniform everywhere, so it will not be so tiring.

First, if the speed is too fast, you will feel tired, and second, riding a bicycle is mainly about the legs, which is more tiring than pushing the whole body.

Yes, as much energy is consumed.

Ever wondered if one is fast and the other is slow. When it's fast, the muscle energy supply rate is high, and when it's high, it's easier to get tired.

A. When going uphill, the height of the bicycle is unchanged, and the route taken by taking the S-shaped route is longer, so A is wrong;

b. The use of any machinery is not provincial, so B is wrong;

c, the speed is certain, the route taken by the S-shaped route is longer, and the time taken is longer, so C is wrong;

D, uphill, take the S-shaped route to take the route is longer, equivalent to increasing the length of the inclined plane, the longer the inclined plane, the more labor-saving so D correct

Therefore, choose D

The speed is the same, and the first time you skate farther. First of all, let the mass of the bicycle and the person be m in total, and the friction coefficient is u, when the slope is on the slope, it can be obtained that the external force of the object is f=mgsina-umgcosa, and the acceleration is a=f m in the direction along the slope. From the above equation, a=gsina-ugcosa, it can be seen that the magnitude of the acceleration is not related to the mass, so the distance from the slope to the slope is the same, the acceleration is the same, and the speed to the bottom of the slope is the same from 2as=v 2.

When gliding on flat ground, it is obvious that the friction force experienced by the first time is smaller than that of the second time, f=un, since the initial velocity is the same, then the acceleration of the first glide is relatively small, and the distance of the glide must be longer.

The resistance to self-movement can be considered to be the same size, k times the weight of the person and the car. The distance of the first glide on the horizontal plane is x1, then the motion theorem is obtained:

mgh-kmgl-kmgx=0

The second time: the same is true:

m'gh-km'gl-km'gx2=0

Comparing the two equations yields x1=x2

The glide distance is the same.

The two times are as great as the speed of the slide to the bottom of the slope, because the acceleration is equal for both times.

The same is true for the two times compared to the glide distance, because the acceleration on the ground is also the same for both times.