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1 A man walks 1.41km directly northeast. What is the component of his displacement in a north direction?
4. Boat is crossing a river. The boat's water carries the boat downstream at a rate such that the resultant velocity of the boat is 6.5m/s. What is the velocity of the water in the river?
5.A man is plowing snow from his driveway. He pushed down teh handle of the plow with a force of 48N with the handle forming an angle of 60 degrees with the horizontal driveway. What is the useful (horizontal) component of the force he exerts down the handle?

4. An aircraft is traveling southwest with a speed of 1410km/h. What is the west compoonent of this velocity?
6. Two dogs are pulling on the same bone. A podle is pulling toward the south with a force of 7N. A spaniel is pulling toward teh east with a force of 24N. With what force and in what directioon must a collie pull on the same bone, if the bone is to have a net force of zero on it? (degrees relative t north)

2007-08-03 19:06:13 · 2 answers · asked by Anonymous in Science & Mathematics Physics

2 answers

1. Northeast is 45º from north. So the north component will be the north displacement time cos(45º)

2. Not enough information--you need to know the boat's velocity directed across the river.

3. The component along the driveway will be 48N*cos(60º). You can always check whether to use sin or cos; if the angle is zero, all the force is along the driveway, and cos(0º) = 1.

4. Just like 1. southwest is 45º from west

5. Form the vector sum of south and east. Since these are 90º apart, the vector sum is the diagonal of a rectangle with sides of 7N and 24N, or √[7^2 + 34^2] = 34.7N That is the magnitude of the cancelling force. The angle that diagonal makes with east is arctan(-7/24)= -16.3º south of east; add 180º to reverse its sign to get 196.3º south of east. To get the angle with respect to north, add another 90º: 286.3º. It helps to draw a diagram.

2007-08-03 19:17:55 · answer #1 · answered by gp4rts 7 · 0 0

1. 1.41/sqrt(2), or 1.00 km.
4. Insufficient data. At least one more number is needed, such as the cross-river component of the velocity.
4b. 1410/sqrt(2). You do the trivial math.
6. This is a simple problem in vector addtion, and I'll leave this one to you to puzzle out. Hint: take components, and add them.

2007-08-03 20:00:26 · answer #2 · answered by Anonymous · 0 0

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