Sheena can row a boat at 2.20 mi/h in still water. she needs to cross a river that is 1.20 mi wide with a current flowing at 1.60 mi/h. not having her calculator ready, she guesses that to go straight across, she should head upstream at an angle of 25.0° from the direction straight across the river.

Part a)

Part b)

Part c)

Part d)

Explanation:

Part a)

Velocity of the boat with respect to water stream is given as

so we have

magnitude of the speed is given as

Part b)

Time to cross the river is given as

Part c)

Distance moved by the boat in downstream is given as

Part d)

In order to go straight we must net speed along the stream must be zero

so we will have

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?