physics

Jack, jill and spot go out for a picnic at the side of the river. jack takes spot for a jog. jack and spot are on the wast bank of the 30m wide river when jill is on the east side. the rivers current is 0.75m/s south.
a) spot jumps into the river and swims straight east at 1.8m/s relitive to the water. once across spot runs 4m/s on the shore to get to jill. How long does to take spot to get to jill?
b)jack dives in the river and aims slightly upstream and swims 2m/s relitive to the water to go straight across. How many seconds does jack beat spot by?

  1. 👍 0
  2. 👎 0
  3. 👁 232
  1. a) time for spot to cross river: 30/1.8
    spot goes this distance downstream*.75*30/1.8
    time for spot to reach jil:30/1.8+distancdownstream/4

    b> Jack swims at arctan .75/2 upstream. His velocity across the river is 2*cosine of that angle, and time across is 30/vacrossriver.

    Do some calculating, and you have it.

    1. 👍 0
    2. 👎 0
    👨‍🏫
    bobpursley
  2. thanks

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. phys

    A car comes to a bridge during a storm and finds the bridge washed out. The driver must get to the other side, so he decides to try leaping it with his car. The side the car is on is 20.2 m above the river, while the opposite side

  2. physics

    Jack drops a stone from rest off of the top of a bridge that is 24.4 m above the ground. After the stone falls 6.6 m, Jill throws a second stone straight down. Both rocks hit the water at the exact same time. What was the initial

  3. Trigonometry

    4. An observer is near a river and wants to calculate the distance across the river. He measures the angle between his observations of two points on the shore, one on his side and one on the other side, to be 28ยบ. The distance

  4. Physics

    A boat starting on one side of the river heads to the south with a speed of 1.5 m/s, the river flows to the east at .8 m/s. What is the resultant velocity to the side of the river? And if the river is 50 m wide calculate the

  1. Physics

    A 10,000N car comes to a bridge during a storm and finds the bridge washed out. The 650-N driver must get to the other side, so he decides to try leaping it with his car. The side the car is on is 16.6 m above the river, while the

  2. Physics

    Jack and Jill exercise in a 25.0-m-long swimming pool. Jack swims nine lengths of the pool in 160.1 seconds (2 minutes and 40.1 seconds), while Jill, the faster swimmer, covers ten lengths in the same time interval. Find the

  3. Classical mechanics

    A boat leaves point P on one side of a river bank and travels with constant velocity V in a direction towars point Q on the other side of the river directly oposite P and distance D from it If r is the instantaneous distance from

  4. Physics

    A car comes to a bridge during a storm and finds the bridge washed out. The driver must get to the other side, so he decides to try leaping it with his car. The side the car is on is 19.5m above the river, while the opposite side

  1. Physics

    A car is traveling on a level horizontal rode comes to a bridge during a storm and finds the bridge washed out. The driver must get to the other side, so he decides to try leaping it with his car. The side of the road the car is

  2. 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

  3. Algebra

    In six years Jill will be twice as old as Amanda. One year ago Jill was nine times older than Amanda. How old is Jill now? I tried 6 + 2x = x because in six years Jill will be twice Amanda's age, but this doesn't work. I need a

  4. word problem

    a farmer has 800 yards of fencing to enclose a rectangular pasture. Since one side of the pasture boarders a river that side does not need to be fenced. if the side perpendicular to the river must be twice as long as the side

You can view more similar questions or ask a new question.