Velocity + expression of a variable from the formula - practice problems
Number of problems found: 135
- Goods train
A goods train runs at the speed of 72 kmph and crosses a 250 m long platform in 26 seconds. What is the length of the goods train?
- The boat
A boatman goes 2 km against the stream in 40 minutes and returns to the same spot in 30 minutes. What is his rate of rowing in still water?
- A plane 3
A plane left 30 minutes later than the scheduled time and in order to reach the destination 1500 km away in time, it has to increase the speed by 250 km/hr from the usual speed. Find its usual speed.
- A long train
A train passes a standing man in 6 sec and 210 m long platform in 16 s . Find the length and the speed of the train.
- Long train
A 110 m long train crosses a tree in 3 s. How long will it take to cross a 165 m long platform and 135 m long bridge, If the platform and bridge are at a distance of 30 m?
- Two trains 11
Two trains running in opposite direction cross a man standing on the platform in 27 seconds and 17 seconds and they cross each other in 23 seconds. Find the ratio of their speeds.
- The speeds
The speeds of three cars are in the ratio 2:3:4. What is the ratio of the times taken by these cars to travel the same distance?
- Three journeys
If a person covers three equal distances at the speed of 30 km/h, 15 km/h and 10 km/h respectively, then find out the average speed during the whole journey.
- Parallel tracks
Two trains cross each other in 14 seconds when running in opposite directions along parallel tracks. The faster train is 160 m long and crosses a lamp post in 12 seconds. If the speed of the other train is 6 km/hr less than the faster one, its length, in
- Lightning strike
In a thunderstorm, the formula M=t/5.3 gives the approximate distance, M, in miles, from a lightning strike if it takes t second to hear the thunder after seeing the lightning. If you are 5.4 miles away from the lightning flash, how long will it take the
- Vertical movement
Find the length of the vertical path you must travel to lift a weight with a force of 0.01 N to do 1 J of work.
- Engine power
Calculate the engine power of a truck moving at a constant speed of v= 30 km/h on a road with a 5% gradient when the weight of the truck with the load m= 5000 kg!
- Horizontal 83148
The bend has a radius of r = 100 m and is inclined at an angle of 20° to the horizontal plane (= tilt angle). What is the safe (the "best") speed to go through this curve? Sketch the picture regarding NIVS, mark the forces, and calculate.
- Braking 83146
A car of mass m=1t moves at a speed v0=54 km/h. What braking force must be exerted to bring the car to a stop in 10 seconds, and how far will the car travel in this time?
- Penetrates 83078
A hammer with a mass of 600 g hits the head of a nail at a speed of 5 m/s. If the nail penetrates 3 cm into the wall, what is the average resistive force of the masonry?
- Overcoming 83076
A battering ram weighing 400 g falls from a height of 3 m. Upon impact, the stake hits a depth of 60 cm. What is the average force overcoming the soil resistance?
- Completely 83045
The diesel tank has a volume of 19.6 hl. The inflow oven, which flows 17.5 l per minute, was opened for 1.5 hours. How long does the inlet pipe need to be opened for the tank to be completely filled?
- Dominika 82882
Dominika and Ninka are in the park. A 48 kg girl sits on the right side of the swing at a distance of 1.9 m from the axis of rotation. Dominika acts on the swing on the left side with a specific force at 2 m from the axis. What force should she exert to k
- Through 82036
5 m³ of water flows through the pipe in 1 second at a maximum speed of 2 m/s. What is the pipe radius?
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