Ask for help from the master to solve the physics problem, please T T 10

Solution: It is known that the mass of the car is m, the maximum power is p, the acceleration is a, the time of motion is t, the distance of motion is s, the original speed v0 = 54km h = 15m s, and the later speed vt = 114km h =

Since there is no mention of resistance or friction factor, we do not consider it.

According to the formula of acceleration motion vt 2-v0 2 = 2as

Because the traction force of the car = mass acceleration, there is pt s=ma, and then according to the acceleration motion formula vt 2-v0 2=2as

Yes: 163 746) t [(.]

So. t=2.Mass = Momentum Velocity = 4875 39 = 125kg

3.Fortunately, you attached the English title, and the quality of the package was not said in the Chinese translation, hehe.

The original state is stationary, let the direction of the package fly out is positive, and the velocity of the ship is v, which can be known according to the conservation of momentum

The momentum of the package - the momentum of the whole made up of the man and the boat = 0, so there is.

v=4.Because the two cars are exactly the same, the center of mass of the system is in a straight line in the northeast direction of 45°, in the velocity triangle formed by the two cars, so the speed of the two cars is v, then there is:

v 2 + v 2 = 50 2, so.

v=5.Because of the inelastic collision, the kinetic energy is not conserved, according to the conservation of momentum, let the velocity of the bullet after the collision be v, the sum of the momentum of the bullet and the wooden block before the collision = the sum of the momentum of the bullet and the wooden block after the collision.

That is: (22 1000) 200+0=(22 1000)v+1

Get: v=-81m s and the direction is left.

Don't think that foreign questions are difficult, these questions are based on the premise of understanding the formulas and unit conversion, and do not put obstacles in your way, if you haven't learned these formulas, go to the reference book.

Greater than Because the initial speed is the same, the greater the mass, the greater the kinetic energy of the trolley, the more work done to overcome the resistance in the process of stopping, and in the case of the same resistance, the longer the distance of the movement (or the mass is large, the inertia is greater, and the distance required for the trolley to stop under the same conditions is longer).

Irrationality! (It's definitely unreasonable to ask so) Because of the different pressures, the friction of the car is different, and it cannot meet the control variables, so it is unreasonable. (f=g=f) because of constant velocity).

This question is the original question of the high school entrance examination.

Greater than the gravitational force of the object, the greater the inertia.

Reasonable: Because of the large mass and large inertia, it is said that in the same situation, the distance used by the large car to stop is longer than that of the small car.

The second regret question: the original Coulomb force between A and B is f1 = k 7q 2 r 2 The result of contact is a, the blue sky lift b and c The final charge is 2q, so the Coulomb force f2 = k 4q 2 r 2f2 = 4 7f1

1) F cannot exceed the maximum static friction, i.e. 2N

2) The acceleration of the wooden block is called a1=3, and the acceleration of the wooden board a2=2, and their displacement is only equal to the length of the wooden board by 2m, that is, a1t 2 2-a2t 2 2=2 solution t=2s

The speed of the plank v=a2t=4m s

3) The blind time 2s in the above question is the time Feng Shenkai sought.

From the conservation of energy, the velocity v at point b is obtained

mgr(1-cosα)+eqrsinα=

Leaving the cylinder at point b, i.e. the cylinder pressure is 0, only by gravity and electric field forces, the perpendicular component of gravity and electric field forces provides the centripetal force of circular motion.

mgcosα-eqsinα=mv²/r……Combine the above two formulas, find e=mg(3cos -2) (3qsin) If you have any questions, please ask, or hi secret talk

The resultant force of the slider is not enough to provide the centripetal force to meet the requirements of the cylindrical surface leaving the cylindrical surface, and the critical condition is taken here to show that the external force along the center of the circle of the slider at point b is exactly equal to the required centripetal force. This answer can be obtained by the kinetic energy theorem 1 2mv2=mgr(1-cosa)+eqrsina mv2 r=mgcosa-eqsina.

Ditto: This condition should be problematic Ignoring the fact that the specific heat capacity of the water is 4200

q=cmδt

The quality of water in the juice A requires the mass of Bing Nianqi block b the mass of juice powder ( the specific heat capacity of the juice powder c the specific heat capacity of the mixture is C mixed = (M1C1 + M2C2) (M1 + M2) Substituting this formula.

Doesn't the specific heat capacity of the juice change when ice cubes are diluted?

Solution: (1) Because the upper surface of the board is smooth, the slider is always stationary to the ground. The force on the analysis slider is n1=mg

The force in the vertical direction of the board is n2=n1+mg

The supporting force of the plank n2 = (m + m) g = (the friction force of the cow plank f = n2 = ox.

2) The plank will eventually stop as long as the plank stops before advancing l=. To the plank:

Acceleration a=f m=20

displacement s=vo (2a).

Then the initial velocity vo 4m s can be obtained from s l

2. The topic is incomplete, please check.

When the second question is 45 degrees, the vertical component of the rope = mg, and the horizontal component of the rope = mg * tan45 = mg = air resistance f

At 14 degrees, the vertical component of the rope = (m+m)g, and the horizontal component of the rope is (m+m)g*tan14, which provides the acceleration in the horizontal direction after subtracting the resistance f.

m+m)g*tan14-mg=（m+m）*

1. The machine can be conserved: grinding blind mgh + mv0 2 2 = mv 2 2v 2 = 2gh + v0 2

v=22m/s

2、δ x=

e=k*δ x^2/2=

downward, the acceleration is (m+m)gsin m

Force analysis of isolated wood panels.

In order for the plank to rest relative to the inclined plane, there must be a force f along the inclined plane, that is, the friction force of man against the board.

fsinθ+ncosθ=mg

fcosθ=nsinθ

The solution yields f=mgsin

According to Newton's third law, the frictional force of the plate against the person is also f, and the direction is downward along the inclined plane.

Re-isolation of human stress analysis.

It can be directly obtained from Newton's second law.

f+mgsinθ=ma

The solution yields a=(m+m)gsin m

Obviously, the direction is down the slope.

People should move upward.

The magnitude of acceleration is: mgsin m

The inclined plane is smooth, and the wooden block must be stationary, and it must be subject to upward friction, which can only be provided by people, so the friction of people is downward, so people have to run upwards.