# Physics

posted by .

A boat travelling at 30km/hr relative to water is headed away from the bank of a river and downstream. The river is 1/2 km wide and flows at 6km/hr. The boat arrives at the opposite bank in 1.24 min.

I calculated the perpendicular component of the boat relative to the water as 24km/hr.
I calculated the total downstream component of the boats motion as 24 km/hr (with the parallel component of the velocity of the boat relative to the water at 18km/hr).
And I calculated the direction in which the boat moves relative to land which is 45degrees to the bank.

I need help with calculating the distance the boat moves downstream as it crosses the river.

• Physics -

I get (0.5/1.24)*60 = 24.2 km/hr for the perpendicular component. Don't do any rounding off yet.
Parallel component of velocity, relative to water = sqrt[(30^2 - (24.2)^2] = 17.7 km/h

The parallel (downstream) velocity of the boat relative to land is 17.7 + 6 = 23.7 km/hr

The distance it drifts downstream in 1.24 minutes *(23.7 km/h)*(1h/60 min)
= 0.49 km

This agrees well with your 45 degree boat direction relative to land . The downstream drift nearly equals the river's width

• Physics -

thank you for the help!

## Similar Questions

1. ### Math

How do I draw the following problem so I have something to refer to when answering a) and b)?
2. ### Physics

A small boat is crossing a river which flows at 10km.h. The driver of the boat keeps it heading directly (at 90) away from the bank at a speed of 24 km/h relative to the water. The river is 0.5 km wide. I calculated the speed of the …
3. ### Physics

A boat is to be driven from a point on the South bank of a river which flows West-to-East to a destination on the North Bank. The destination is in a direction of N60E from the starting point. The river is 0.2 km wide. The driver of …
4. ### Physics

A boat travelling at 30km/h relative to water is headed away from the bank of a river and downstream. The river is 1/2 km wide and flows at 6km/h. The boat arrives at the opposite bank in 1.25min. Calculate the component of the boat's …
5. ### Physics

A boat travelling at 30km/h relative to water is headed away from the bank of a river and downstream. The river is 1/2 km wide and flows at 6km/h. The boat arrives at the opposite bank in 1.25min. Calculate the component of the boat's …
6. ### Physics

A boat travels at 3.8 m/s and heads straight across a river 240m wide at an angle of 145'. The river flows at 1.6 m/s. a. What is the boat's resultant speed with respect to the river bank?
7. ### Physics

A boat travels at 3.8 m/s and heads straight across a river 240m wide at an angle of 145'. The river flows at 1.6 m/s. a. What is the boat's resultant speed with respect to the river bank?
8. ### Physics

A boat travels at 3.8 m/s and heads straight across a river 240m wide at an angle of 145'. The river flows at 1.6 m/s. a. What is the boat's resultant speed with respect to the river bank?
9. ### physics

A 400.0-m-wide river flows from west to east at 30.0 m/min. Your boat moves at 100.0 m/min relative to the water no matter which direction you point it. To cross this river, you start from a dock at point A on the south bank. There …
10. ### Physics

A 400.0-m-wide river flows from west to east at 30.0 m/min. Your boat moves at 100.0 m/min relative to the water no matter which direction you point it. To cross this river, you start from a dock at point A on the south bank. There …

More Similar Questions