Tilted Forum Project Discussion Community - View Single Post - Calculus

threewingedfury · 10-16-2005, 10:16 AM

Ok.. I'm new to this place.. but I see that you guys do help with calc.. which is good since people at NCSU don't like helping others.. but anyways.. I'm having a serious problem with related rates. I don't know if its the fact that I can't put 2 and 2 together or I can't draw a picture that makes sense. And on top of all that, I hate calculus. So without furthur adue.. these are the problems I'm struggling with:

1. At 2 P.M., ship A is 150 km west of ship B. Ship A is sailing east at 35 km/h and ship B is sailing north at 25 km/h. How fast is the distance between the ships changing at 6 P.M.?

2. A spotlight on the ground shines on a wall 12 m away. If a man 2 m tall walks from the spotlight toward the building at a speed of 2.3 m/s, how fast is the length of his shadow on the building decreasing when he is 4 m from the building?

3. A boat is pulled into a dock by a rope attached to the bow of the boat and passing through a pulley on the dock that is 1 m higher than the bow of the boat. If the rope is pulled in at a rate of 1 m/s, how fast is the boat approaching the dock when it is 8 m from the dock?

4. Water is leaking out of an inverted conical tank at a rate of 10500 cm3/min at the same time that water is being pumped into the tank at a constant rate. The tank has height 6 m and the diameter at the top is 4 m. If the water level is rising at a rate of 20 cm/min when the height of the water is 2 m, find the rate at which water is being pumped into the tank.

And no I'm not asking anyone to do my homework, but if someone could just show me the method that would help me get the idea of how to do it, I'd appreciate it.

10-16-2005, 10:16 AM	#1 (permalink)
threewingedfury Upright	Calculus - Related Rates Ok.. I'm new to this place.. but I see that you guys do help with calc.. which is good since people at NCSU don't like helping others.. but anyways.. I'm having a serious problem with related rates. I don't know if its the fact that I can't put 2 and 2 together or I can't draw a picture that makes sense. And on top of all that, I hate calculus. So without furthur adue.. these are the problems I'm struggling with: 1. At 2 P.M., ship A is 150 km west of ship B. Ship A is sailing east at 35 km/h and ship B is sailing north at 25 km/h. How fast is the distance between the ships changing at 6 P.M.? 2. A spotlight on the ground shines on a wall 12 m away. If a man 2 m tall walks from the spotlight toward the building at a speed of 2.3 m/s, how fast is the length of his shadow on the building decreasing when he is 4 m from the building? 3. A boat is pulled into a dock by a rope attached to the bow of the boat and passing through a pulley on the dock that is 1 m higher than the bow of the boat. If the rope is pulled in at a rate of 1 m/s, how fast is the boat approaching the dock when it is 8 m from the dock? 4. Water is leaking out of an inverted conical tank at a rate of 10500 cm3/min at the same time that water is being pumped into the tank at a constant rate. The tank has height 6 m and the diameter at the top is 4 m. If the water level is rising at a rate of 20 cm/min when the height of the water is 2 m, find the rate at which water is being pumped into the tank. And no I'm not asking anyone to do my homework, but if someone could just show me the method that would help me get the idea of how to do it, I'd appreciate it.