The river velocity, being perpendicular to the crossways motion of the boat, does not affect the time to cross the river. Any alteration in the river velocity will have no affect upon the time to cross the river.
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How do you solve river boat problems in physics?
How do you calculate the drift on a river boat problem?
The boat cannot cross the river to an exactly opposite point. In this case, the drift is minimum if โvb=โvb/w+โvw v โ b = v โ b / w + v โ w is perpendicular to โvb/w v โ b / w . The angle made by โvb/w v โ b / w with โvw v โ w is given by ฮธ=cosโ1โvb/wvw=cosโ1โ12=150degree.
When a boat tends to cross a river along the shortest path?
When he crosses a river with shortest time one component of boat velocity is opposite to velocity of water and other component is perpendicular to velocity of water.
What happens if the river direction time is too large?
EXPLANATION: Reverberation is the time taken for the sound to fall below the minimum audibility measured from the instant when the source stopped sounding. Therefore if the reverberation time becomes too large it produces an echo. So option 2 is correct.
What is the physics in boat?
If the buoyant force is equal to or greater than the weight of the object, the object floats. In physics, this is known as the Archimedes Principle. For a boat to float, enough of the boat’s surface must make contact with the water to generate the proper force of buoyancy.
How do you solve crossing the river problem?
Why is it difficult to cross fast flowing river using a boat?
The river moves downstream parallel to the banks of the river. As such, there is no way that the current is capable of assisting a boat in crossing a river.
How do you do a river boat problem?
What is drift in river problems?
Answer: Due to speed of water flow in river, a person either swimming or floating stationary in the river experiences a pushing force along the flow direction.
What is the formula for minimum drift?
to find minimum D, we differentiate and then equate to 0 dDdt=0utโvsin(x)t=D. If we have the velocity of the boat and the velocity of the river, then we can find the angle for which drift is minimum for that particular velocity of boat using the above relation.
How do you cross the river in shortest distance?
To cross the river in shortest distance, he should swim making an angle ฮธ with the upstream.
How do you cross a river in the shortest time?
(i) Shortest time : To cross the river by the shortest time, he has to be rowed perpendicular to the river. As a result of the river velocity the person will reach a point say C from A. (drawn the current).
How fast is the river flowing physics?
The speed of a river varies from close to 0 m/s to 3.1 m/s (7 mph). Factors that affect the speed of a river include the slope gradient, the roughness of the channel, and tides. Rivers tend to flow from a higher elevation to a lower elevation.
Does water flow faster in a wide river?
Generally a narrower, more circular river channel allows faster flow of water. Broader flat channels tend to slow a river down.
Why do rivers flow faster than water flowing into a well?
This means that less of the water is in contact with the bed of the river and the mouth so there is less energy used to overcome friction. Hence rivers flow progressively faster on their journey downstream. Width and depth increases as more water is added from tributaries.
What is Sabines law?
Sabine came up with a formula that architects and engineers could use when designing a concert hall so they could achieve the best reverberation time for their particular venue. Sabine found that 2 to 2.25 seconds was an optimal reverberation time for a concert hall, and around 1 second was optimal for a lecture hall.
Why does a river flow faster in the middle?
The laminar flow is a function of the depth of the river. Since the channel is normally deeper in the middle and decreases in depth to the shore, the current in the center or deepest part of the channel is faster than current close to the shore.
What three factors affect how fast a river flows?
- Volume of water.
- Rock structure.
- Slope of the terrain.
- Amount of sediments.
Does river velocity increase or decrease downstream?
Because river slope generally decreases in a downstream direction, it is generally supposed that velocity of flow also decreases downstream. Analysis of some of the large number of velocity measurements made at stream-gaging stations demonstrates that mean velocity generally tends to increase downstream.
What causes the boat to move forward physics?
Propulsion A boat accelerates through the action/reaction principle (Newton’s 3rd Law). You move water one way with your oar, the boat moves the other way. The momentum (=mass x velocity) you put into the water will be equal and opposite to the momentum acquired by the boat.
Why does the boat not move in still water?
It is the force of friction between the surface of water and the boat that brings the boat to rest once we stop rowing. Was this answer helpful?
What are the forces acting on a boat?
When a boat is in the water, there are two forces acting on it: 1) weight (pushing down) and 2) buoyancy (pushing up). The boat floats in the water because the two forces are balanced (weight = buoyancy). The “weight” force exists because of gravity acting on the boat.
What is it that even crossing the river does not get wet?
The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it? Answer: The river is frozen.
Can you get all four across the river safely?
Can you get all four across the river safely? Only the man and at most one other item are allowed in the boat for each crossing. Only the man is able to operate the boat. Do not leave the goat alone with the carrots or the wolf unsupervised with the goat.