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1、 Judge whether the two quantities in the following questions are in proportion, and explain the reasons. (1) the driving time of the car is fixed, the driving distance and speed 1、 Judge whether the two quantities in the following questions are in proportion, and explain the reasons (1) The time, distance and speed of a car are fixed (2) The amount of money and stops needed to buy a ticket on a bus (3) The price of each TV set is fixed, the number of TV sets to buy and the amount of money 2、 Use the equation to express the quantitative relationship in the following questions (1) A car can travel 180 km in 3 hours and 300 km in 5 hours (2) A pile of flour, 4 bags of 200kg, 6 bags of 300kg
1、 2. The more money you spend on tickets, the more stops you take. 3. The price of each TV set is fixed. The more TV sets you buy, the more you need
When moving at a constant speed, is time proportional to distance?
reason
I think when the speed is 0, it's not
When the velocity V is constant, the distance s is proportional to the time t
When the road resistance is constant, the uniform speed of the car is inversely proportional to the actual power of the engine?
P = w / T = FS / T = Fv (speed)
Because of the uniform velocity, f = F
Then p = FV when the road resistance is constant, the uniform speed of the vehicle is proportional to the actual power of the engine
Suppose that the resistance of a car is proportional to the speed of the car. If the power of the engine is p when the car runs at a constant speed of V, then the power of the engine is ()
A. PB. 2 PC. 3 PD. 4 P
When the speed is 2V, the resistance f ′ = 2KV, the power of generator P ′ = f ′· 2V = 4kv2 = 4P. So D is correct, a, B and C are wrong. So D is selected
RELATED INFORMATIONS
- 1. When the vehicle runs at a constant speed V, the power of the engine is p. if the resistance of the vehicle in motion is equal to What is the power of the engine when the car is running at 2V?
- 2. 1. On the slope with a sine value of 1 / 10, a car runs with constant power, and the friction resistance is 2 / 10 of the weight of the car. If the speed rate of the car going up the slope at a constant speed is V, what is the speed rate of the car going down the slope at a constant speed? 2. The vehicle accelerates on the horizontal road with constant power and constant resistance. When the speed is V, the acceleration is a, and when the speed is 2V, the acceleration is a / 4, what is the maximum speed of the vehicle?
- 3. If the engine power is kept unchanged, the speed of the car is v2 What is the maximum speed of the car on the horizontal road with the same amount of power (assuming that the resistance of the car is the same in three cases)?
- 4. A ton of coal carries 25 tons, which is just five twelfth of the total tons. If it carries 60% of the total tons, how many tons?
- 5. A pile of coal carries 25 tons, which is just five twelfth of the total tons. If it carries 60% of the total tons, how many tons?
- 6. When are fractional values, numerators, and denominators in positive proportion
- 7. If the denominator is fixed, the proportion between the numerator and the fractional value depends on the quantitative relationship
- 8. The numerator is proportional to the denominator and the denominator is proportional to the fraction
- 9. The volume of a cube is not proportional to its surface area Judgment questions It's a judgment question,
- 10. The surface area of a cube is in direct proportion to its edge length. Why?
- 11. Can the distance and time of driving be in direct proportion? What's the reason?
- 12. If a car goes from place a to place B at a speed of 40 kilometers per hour, it will arrive at the scheduled time. In fact, the car has been driving for three hours The speed slowed down to 30 km / h, so it was one hour later than expected
- 13. The speed of a car driving from Tianjin to Beijing is out of proportion to the time it takes
- 14. The mass of a car with rated power P is m. It starts from standstill on a straight road. If the traction of the car remains unchanged during the starting process, the resistance in the process of movement is u times that of the car. What is the maximum acceleration time
- 15. A car accelerates uniformly at rated power and is subject to resistance and traction Then f should be the smallest in P = f * v. is this f resistance, traction or resultant force?
- 16. Locomotive starting with constant power and locomotive starting with constant traction (acceleration) The teacher spoke very fast in class and didn't understand much,
- 17. A transport team carries 64.5 tons of goods in the first day, 18.5 tons more in the second day than in the first day, and three times more in the third day than in the previous two days. How many tons of goods are transported in the three days?
- 18. A transport team carries 78.5 tons of goods in the first day, which is 1.5 tons less than 1.6 times of the next day's volume. How many tons of goods will be transported in the next day
- 19. A batch of timber was sold in the first morning, half of which was sold in the afternoon, and three tons in the afternoon. The next morning, half of the remaining timber was sold, and three tons in the afternoon One morning, half of the remaining timber was sold, and in the afternoon, three tons were sold. At this time, one ton of timber was left. How many tons of timber did the timber factory have?
- 20. A production team transported a batch of grain, 1104 kg on the first day, and a quarter more on the second day than on the first day. In two days, it transported 40% of this batch of grain A production team transports a batch of grain, 1104kg on the first day, and a quarter more on the second day than on the first day. It transports 40% of this batch of grain in two days, and the rest is planned to be transported in two days. How many kg do you transport in these two days?