# physics

posted by .

Your English teacher can swim with a constant speed of 0.67m/s. While facing south , he attempts to swim straight across the St. Lawrence River , which moves east at 1.4 m/s
a) find his velocity as seen from the riverbank.

B) if the river was 175m wide
How long does it take him to cross the
River

Hri

• physics -

teacher: v1=0.67 m/s,
river: v2 =1.4 m/s,
v=sqrt(v1²+v2²) =1.55 m/s. (to the east of south)
L =175 m,
s=?
v/v1=s/L =>
s= v•L/v1 =1.55•175/0.67 =404 m.
t=s/v =404/1.55 =260 s =4.34 min

## Similar Questions

1. ### physics

You want to swim straight across a river that is 76m wide. You find that you can do this if you swim 28 degrees upstream at a constant rate of 1.7m/s relative to water. At what rate does the river flow?
2. ### Physics

A river 99.1 m wide flows toward the south at 31.5 m/min. A girl on the west bank wishes to reach the east bank in the least possible time. She can swim 99.1 m in still water in 1.80 min. What is her velocity relative to land?
3. ### Physics

Veronica can swim 3.0 m/s in still water. While trying to swim directly across a river from west to east,?
4. ### Physics_Vectors

You can swim at a speed v relative to the water. You are swimming across a river which flows at a speed V relative to the shore. The river is straight and has a constant width. A. If you wish to swim directly across the river, in what …
5. ### Algebra and Trigonometry

A person who can swim at 3 m/s wishes to swim straight across a river flowing at 2 m/s south. What heading should they swim at?
6. ### Physics

You wish to swim across a small river to your friend on the other side. The river is 30 m wide and you begin to swim straight across it at a speed of 1 m/s. The current in the river is 0.5 m/s and so the river carries you downriver …
7. ### physics

Noah wants to swim across a river 10 m wide, flowing from north to south. He swims so his velocity with respect to the river is 2 m/s due east, and the river moves at 4 m/s. How far downstream in m from his starting point will he reach …
8. ### physics

Noah wants to swim across a river 10 m wide, flowing from north to south. He swims so his velocity with respect to the river is 2 m/s due east, and the river moves at 4 m/s. How far downstream in m from his starting point will he reach …
9. ### Physics

Vanessa can swim 3.0 m/s in still water. While trying to swim directly across a river from west to east, Vanessa is pulled by a current flowing southward at 2.0 m/s. A) What is the magnitude of Vanessa’s resultant velocity?
10. ### Physics

Vanessa can swim 3.0 m/s in still water. While trying to swim directly across a river from west to east, Vanessa is pulled by a current flowing southward at 2.0 m/s. A) What is the magnitude of Vanessa’s resultant velocity?

More Similar Questions