Question

The resulting motion of a boat on a river is 20 km/h in a direction making an angle of 60 degrees with the current. If the river is 1.5 km wide, how long does it take the boat to cross the river? The resulting motion of a boat on a river is 20 km/h in a direction making an angle of 60 degrees with the current. If the river is 1.5 km wide, how long does it take the boat to cross the river? @Physics

Answer 1

Make a diagram of the question. I assume the current is travelling along the river perpendicular to the width of the river. Let's imagine the current is the y-axis and the width of the river would be along the x-axis.
The direction of motion of the boat should be 60 degrees to the y-axis. You should have made a right-angled triangle.
Can you see how to find the x-component of the velocity using either cos or sin?

Answer 2

yea, but how about the other problem