The swimmer

The swimmer swims at a constant speed of 0.85 m/s relatives to water flow. The current speed in the river is 0.40 m/s, the river width is 90 m. a) What is the resulting speed of the swimmer with respect to the tree on the riverbank when the swimmer's motion is perpendicular to the current? b) How long does the swimmer cross the river?

Correct answer:

v =  0.9394 m/s
t =  105.8824 s

Step-by-step explanation:

$$\begin{gathered} v_1=0.85\text{ m/s } \\ {v}_2=0.40\text{ m/s } \\ s=90\text{ m } \\ v=\sqrt{v_1^2+v_2^2}=\sqrt{0.85^2+0.4^2}=0.9394\text{ m/s} \end{gathered}$$

$t=s\mathrm{/}{v}_1=90\mathrm{/}0.85=105.8824\text{ s}$

Try another example

Related math problems and questions:

• Paratrooper
  After the parachute is opened, the paratrooper drops to the ground at a constant speed of 2 m/s, with the sidewinding at a steady speed of 1.5 m/s. Find: a) the magnitude of its resulting velocity concerning the ground, b) the distance of his land from a
• Tarzan
  Tarzan, weighing m = 90 kg, tries to cross the river by swinging with a vine hanging from a tree leaning over the river. Liana has a length l = 12 m. The speed of the Tarzan in the lowest swing position is v = 8 m/s. Tarzan doesn't know that the liana wil
• Cars motion
  From point A car start at the speed of 90 km/h. Against it departs from the point B at the same time another car at 60 km/h. For how long and where they met if the distance between A and B is 180 km?
• Cruise liner
  Cruise liner runs along the river between points A and B. The journey downstream takes 40 minutes 1 hour upriver. The flow rate of the river is 3 km/h. What is the speed of cruise liner?
• Free fall
  For how long and at what speed does the body fall to the ground during a free fall from a height of 35 m?
• Acceleration 2
  if a car traveling at a velocity of 80 m/s/south accelerated to a velocity of 100 m/s east in 5 seconds, what is the cars acceleration? using Pythagorean theorem
• Water current
  John swims upstream. After a while, he passes the bottle, from that moment he floats for 20 minutes in the same direction. He then turns around and swims back, and from the first meeting with the bottle, he sails 2 kilometers before he reaches the bottle.
• Two trains
  Through the bridge, long l = 240m, the train passes through the constant speed at time t1 = 21s. A train running along the traffic lights at the edge of the bridge passes the same speed at t2 = 9s. a) What speed v did the train go? b) How long did it take
• The cruise ship
  The cruise ship has a speed of 12 km/h at a calm surface. When we sail 45 km along the river and 45 km back, it took us exactly 8 hours. Which (constant) speed of flow of the river?
• Motion 2
  At 10 o'clock started from place A car speed at 90 km/h. 20 minutes after started from the place B at speed 60 km/h another car. Distance places A and B is 120 kilometers. What time and where they meet?
• Train 2
  The train slowed down from 90 km/h to 72 km/h in 5 seconds. How long track travel?
• Two aircraft
  From the airport will start simultaneously two planes, which fly tracks are perpendicular to each other. The first flying speed of 680 km/h and the second 840 km/h. Calculate how far the aircraft will fly for half an hour.
• Driver
  The car driver drives at a speed of 100 km/h, saw the obstacle, and began to brake with a slowing of 5 m/s². What is the length of the pathway to stopping the car when the driver has registered the obstacle with a delay of 0.7 s?
• The shooter
  The shooter heard the impact of the bullet on the target in one second after the shot. The bullet was moving at an average speed of 500 m/s. Calculate with speed of sound of 340 m/s. Determine the distance of the target.
• River
  From the observatory 11 m high and 24 m from the riverbank, river width appears in the visual angle φ = 13°. Calculate the width of the river.
• The tram
  The tram is moving with acceleration a = 0.3m/s2. How long will it pass the first meter of the track? How long does it take 10 meters? What is its speed at the end of the 10 meters track?
• Acceleration
  The car accelerates at rate 0.5m/s². How long travels 400 meters and what will be its speed?