hi,
there is 2 exercises on relative velocity that i don't really understand. If someone could give a hint:
1-calculate the time needed to swim across a river 142m wide when the swimmer can swim at 2km/h in still water and the river is flowing at 1km/h. At what angle to the bank should the swimmer swim?
--- so i found 142m/2000m/h = 0.071h = 4.26 minutes = 4 minutes 15.6 seconds [the proposed answer is 4 minutes 55 seconds] ? I don't know how to calculate the angle?
2- a ship is heading in a direction N60S at a speed in still water would 20km/h. It is carried off course by a current of 8km/h in a direction of E50S. Calculate the ship's actual speed and direction?
--- speed sqrt(20^2+8^2)=21.54km/h [proposed answer is 22.79 km/h]? again don't know how to calculate the direction [answer should be E9.78N]
thank you for your help
there is 2 exercises on relative velocity that i don't really understand. If someone could give a hint:
1-calculate the time needed to swim across a river 142m wide when the swimmer can swim at 2km/h in still water and the river is flowing at 1km/h. At what angle to the bank should the swimmer swim?
--- so i found 142m/2000m/h = 0.071h = 4.26 minutes = 4 minutes 15.6 seconds [the proposed answer is 4 minutes 55 seconds] ? I don't know how to calculate the angle?
2- a ship is heading in a direction N60S at a speed in still water would 20km/h. It is carried off course by a current of 8km/h in a direction of E50S. Calculate the ship's actual speed and direction?
--- speed sqrt(20^2+8^2)=21.54km/h [proposed answer is 22.79 km/h]? again don't know how to calculate the direction [answer should be E9.78N]
thank you for your help
