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1) From the high platform to the landing time t=(2h g) (1 2)=The distance between the landing point of the motorcycle and the high platform should be, and your topic is 75m, which is inconsistent with the reality.

The horizontal velocity after rushing to the high platform v0=s t=

2) After 1s landing, the vertical speed when landing v1=gt=10 when landing speed v=(v0 2+v1 2) (1 2)3) the speed of the motorcycle when rushing to the high platform v2=10m s, the speed after rushing is v0 = motorcycle traction is w1 = pt=

Gravity does negative work, i.e., w2=-mgh=

The resistance does negative work, which is w3

According to the kinetic energy theorem, there is.

w1+w2+w3=(mv0^2-mv2^2)/21800*16-1800*5+w3=90*(w3=

h=1/2gt^2 h=5m t=1s

s=75 s=vt v=75m/s

p=fv at rated power v start = v end.

v start = I don't know the picture, I can't do it anymore.

Summary. 1 Impulse (1) Definition: The product of the force and the time of action of the force (2) Formula:

i ft, which is suitable for finding the impulse of a constant force (3) direction: the same direction as force f 2 momentum (1) definition: the product of the mass of an object and its velocity (2) Formula:

p＝mv.(3) Unit: kilograms, meters, seconds, symbol:

kg·m/s.(4) Significance: Momentum is a physical quantity that describes the state of motion of an object, and it is a vector quantity, and its direction is the same as the direction of velocity

Hello! Send the question, you can take a picture and send it.

How do you use the momentum theorem column?

And I don't understand what the impulse is.

You first understand the momentum theorem (1) Content: The impulse of the net force on the object is equal to the increment of the momentum of the object (2) Expression: f·δt δp p p

3) Vector: The direction of momentum change is the same as that of the resultant land crack, and the momentum theorem can be used in a certain direction

I guess it's not the support of the earth.

The f here is the resultant force.

So the support force is subtracted by gravity, but the support force is varied, so it is multiplied by time.

And the support force is the impulse?

1 Impulse (1) Definition: Product of Force and Force Action Time (2) Formula: i ft, applicable to finding the impulse of a constant force (3) Direction:

The same direction as the force f 2 volt momentum Huizhou impulse (1) Definition: the product of the mass and velocity of the object (2) Formula: p mv

3) Unit: kilograms·meters and seconds, symbol: kg·m s.

4) Significance: Momentum is a physical quantity that describes the state of motion of an object, and it is a vector quantity, and its direction is the same as that of velocity

Impulse is not a supporting force, there are two forces here, one gravity and one support, both can be used as impulses, but in the end people are a whole problem.

Overall. So, at this time, it should be the resultant force of gravity and the supporting force as the impulsive force.

So at the end of the day, when the support force is equal to the gravitational force, is the support force still the impulse force in the book? If so, is the end of the twig impulse equal to gravity? So the impulse is to change from zero to big and then small, and finally equal to Chongzhou search force?

The impulse should change from large to small.

Because the athlete is falling, there is no buffer time when touching the mat.

This time is getting smaller.

Later, it became 0

Because the balance of the three forces can be equivalent to the resultant force of the first two forces and the balance of the third force of Xun pants, it becomes the positive and simple balance of the two forces. Liquidation.

In this way, the third force is removed, and only the resultant force of the first two forces remains, i.e., a force of the same magnitude in the opposite direction to the third force.

So the direction is the opposite of f3, and the magnitude of the force is calculated from f=ma as 4n

High school ones. No, it won't.

The direction is the same as f3.

Untie; aMove in the direction of gravity.

f=maf3= × =4n

If the water temperature in the test tube is raised or lowered, heat exchange is achieved through the test tube. But the effect is not the same, because when heating, the water in the test tube is easy to achieve convection, because the hot water rises upward, and the bottom of the test tube plays its main role; In cooling, it is different, the water in the test tube is not easy to form convection, and the cooling at the bottom of the test tube does not work, and can only be cooled by the test tube on the side wall. Choose C.

Because the convection of heat is upward.

Heating is generally carried out underneath.

So the first time it was hot underneath, so the speed was faster than the second time.

The heat exchange of a large amount of water at the bottom is 60 fast, 1. The water temperature polymer moving block.

2. The convection of heat goes up (low density).