- Joined
- Mar 12, 2007
- Messages
- 364
- Reaction score
- 1
In section 2 of berkeley review, passage 7, the passage describes a skiier being pulled up a mountain by a tow rope. There are a couple of questions where we have to write out the forces acting on the skiier. What i dont get is that i thought friction opposed the motion of the skiier.
-For #43 it asks to write out the equation for the minimum tension the tow rope must provide to keep the skier moving up the hill. The skiier is on a picture of an inclined plane with the tow rope attached, pulling him up. The forces acting are the Tension in the rope up the hill, friction down the hill, normal force perpendicular and gravitational force straight down. I get all that.
But THEN, for #44, it says "a skier has to side step up a hill and turns her skis perpendicularl to the hill and makes a series of small steps up the hill. The max steepness of a hill that a skier can side step is determined by?
In the answer diagram, they drew the forces and they have the friction force going IN the direction of motion. I thought its supposed to be the other way?
-Also for #46 it says a skier skies down a curved hill. As the skier skis down the hill, which of the following concering his acc and speed is true?
a. the speed decreases and acc increases
b. speed increases and acc decreases
c. both speed and acc increase
d. both the speed and acc decrease
I thought that since the skiier is going down, the angle of inclination is getting smaller so the acceleration is decreasing, which means speed decreases. The answer is that the angle is getting BIGGER. How is that possible?? Isn't going from the top of something to the bottom of an inclined plane means that the angle is getting smaller? what am i missing here...its prob really simple and i just dont understand it!
-For #43 it asks to write out the equation for the minimum tension the tow rope must provide to keep the skier moving up the hill. The skiier is on a picture of an inclined plane with the tow rope attached, pulling him up. The forces acting are the Tension in the rope up the hill, friction down the hill, normal force perpendicular and gravitational force straight down. I get all that.
But THEN, for #44, it says "a skier has to side step up a hill and turns her skis perpendicularl to the hill and makes a series of small steps up the hill. The max steepness of a hill that a skier can side step is determined by?
In the answer diagram, they drew the forces and they have the friction force going IN the direction of motion. I thought its supposed to be the other way?
-Also for #46 it says a skier skies down a curved hill. As the skier skis down the hill, which of the following concering his acc and speed is true?
a. the speed decreases and acc increases
b. speed increases and acc decreases
c. both speed and acc increase
d. both the speed and acc decrease
I thought that since the skiier is going down, the angle of inclination is getting smaller so the acceleration is decreasing, which means speed decreases. The answer is that the angle is getting BIGGER. How is that possible?? Isn't going from the top of something to the bottom of an inclined plane means that the angle is getting smaller? what am i missing here...its prob really simple and i just dont understand it!