A family decided to take a canoe trip one summer. After paddling for an hour, they decided to drift along with the river current to take a break. When they stop, the canoe is traveling east at 1.3 m/s while the river current is moving 0.2 m/s to the west. When the canoe drifts into the path of another river that joins the first, the west-moving current is 0.8 m/s. How will the canoe be affected?

 v_c = 0.7 m / s    east

Explanation:

This is a one-dimensional velocity addition problem.

1 part

The canoe goes to v_ = 1.3 m / s towards the east and the river goes to

v_r = 0.2 m / s towards the west, if we assume that the direction towards the east is positive v_r = -0.2 m / s

the speed of the canoe with respect to the land is the speed of the canoe with respect to the river plus the speed of the river with respect to the land

             v_c = v_{cr} + v_r

             v_{cr} = v_c - v_r

             v_{cr} = 1.3 - (-0.2)

             v_{cr} = 1.5 m / s

this is the speed of the with respect to the river.

2 part

now we enter a river that the speed is v_r = -0.8 m / s, therefore the speed of the canoe with respect to the land is

              v_c = v_{cr} + v_r

              v_c = 1.5 - 0.8

              v_c = 0.7 m / s

the positive sign indicates that it continues to move east

a small object of mass 3.66 g and charge -17.6 µc is suspended motionless above the ground when immersed in a uniform electric field perpendicular to the ground. what are the magnitude and direction of the electric field?

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.