# Search results

1. ### Simple angular speed problem

can anyone else also confirm this answer?
2. ### Simple angular speed problem

A student is sitting on a frictionless rotating stool with her arms outstretched holding equal heavy weights in each hand. If she suddenly let's go of the weights, her angular speed will: A) increase B) stay the same C) decrease attempt: i think it's B because angular speed is V/r and...
3. ### Two points are on a disk that rotates about an axis perpendicular to the plane

Two unequal masses m and 2m are attached to a thin bar of negligible mass that rotates about an axis perpendicular to the bar. When m is a distance 2d from the axis and 2m is a distance d from the axis, the moment of inertia of this combination is I. If the masses are now interchanged, the...
4. ### Simple rotational motion point problem

ok. i think its V/2?
5. ### Simple rotational motion point problem

Two points are on a disk that rotates about an axis perpendicular to the plane of the disk at its center. Point B is 2.00 times as far from the axis as point A. If the linear speed of point is V, then the linear speed of point A is I know the speed of A must be less and i think its V/4. Is...
6. ### Simple rotational motion problem

Two identical merry-go-rounds are rotating at the same speed. One is crowded with riding children; the other is nearly empty. If both merry-go-rounds cut off their motors at the same time and coast to a stop, slowed only by friction (which you can assume is the same for both merry-go-rounds)...
7. ### Simple gravitational attraction forces problem

you said it is 5.11 N. isn't it 5.11E-8 N?
8. ### Simple gravitational attraction forces problem

calculations: D acting on A: F=(6.673E-11)[4/.1414^2]. i got the .1414 from pythagorean using .1 as a and b. F=1.3346E-8 B acting on A: F=(6.673E-11)[4/.1^2] F=2.669E-8 --> but this is not downward pull using SOH CAH TOA i did cos(45)=x/2.669E-8 x=1.89E-8 --> this needs to be multiplied by...
9. ### Simple gravitational attraction forces problem

i re-did it and got 6.67E-8 is this correct?
10. ### Simple gravitational attraction forces problem

before i write it all out is this the right method?
11. ### Simple gravitational attraction forces problem

Each mass in the figure below is 2.00. Find the magnitude of the net gravitational force on mass A due to the other masses in figure b (the square). Figure: http://i.imgur.com/fjSgU.jpg attempt: i used the formula F=G [(m1*m2)/r^2]. all of the forces are in the direction of D so i...
12. ### Simple block tension Newton gravity problem

The 4.00kg block in the figure is attached to a vertical rod by means of two strings. when the system rotates about the axis of the rod, the strings are extended and the tension in the upper string is 80N. A: What is the tension in the lower cord? B: what is the speed of the block? FIGURE...
13. ### Hanging Balls tension problem

the second part of the questions asks "Find the force the balls exert on each other." i think the only force they have on each other is the x component of tension. so I am guessing the answer is 78.6cos(65)=33.2. but the problem gives the diameter of the balls and i haven't used that number...
14. ### Hanging Balls tension problem

thank you very much
15. ### Hanging Balls tension problem

ok i think i got it. is it 71.2/cos(25) = 78.56?
16. ### Hanging Balls tension problem

the tension force is diagonal. 71.2 is the weight of each ball. here is the diagram: http://i.imgur.com/Q5dXO.jpg
17. ### Hanging Balls tension problem

i think i see my mistake. should it be cos(25)*71.2 = 64.5 Newtons?
18. ### Hanging Balls tension problem

Two identical, perfectly smooth 71.2 {\rm N} bowling balls 21.7 {\rm cm} in diameter are hung together from the same hook in the ceiling by means of two thin, light wires, as shown in the figure. The balls are touching with an angle of 50 degrees between the two wires split evenly between the...
19. ### Simple sum of forces parachute problem

i think the force exerted by the ground on the man is upward? should my answer be positive?
20. ### Simple sum of forces parachute problem

a 64 kg parachutist falling vertically at a speed of 6.3 m/s impacts the ground, which brings him to a complete stop in a distance of .92 m. assuming constant acceleration after his feet first touch, what is the average force exerted on the parachutist by the ground? i know: Vf=0 Vi=6.3...
21. ### Simple vector train problem drawing

A ball is hanging from a long string that is tied to the ceiling of a train car traveling eastward on horizontal tracks. An observer inside the train car sees the ball hang motionless. Draw a clearly labeled free-body diagram for the ball if the train has a uniform velocity. i drew two...
22. ### Simple vector on a train drawing problem

The problem statement, all vaA ball is hanging from a long string that is tied to the ceiling of a train car traveling eastward on horizontal tracks. An observer inside the train car sees the ball hang motionless. Draw a clearly labeled free-body diagram for the ball if the train has a...
23. ### Dogs pulling on a post vector probelm

im going to trust you on this one
24. ### Dogs pulling on a post vector probelm

ok but the question says that the dogs pull "horizontally." This means that they are both pulling on the x-axis, and their angle is created in the y-axis. isn't the wording unclear?
25. ### Dogs pulling on a post vector probelm

i'm very good at vector adition, but i don't know how to divide these two vectors into their components. if i had angles for each vector i would understand how to do the problem
26. ### Dogs pulling on a post vector probelm

ok. i know not to split the angle, but now i don't know how to get started.
27. ### Dogs pulling on a post vector probelm

Two dogs pull horizontally on ropes attached to a post; the angle between the ropes is 60.5. If dog A exerts a force of 250 and dog B exerts a force of 330 , find the magnitude of the resultant force. Find the the angle the resultant force makes with dog A's rope. -I don't know where...
28. ### A coyote chases a rabbit basic vector problem

can anyone else confirm this is true?
29. ### A batter hits a baseball motion and velocity problem

dont give me TOO much advice
30. ### A batter hits a baseball motion and velocity problem

A batter hits a baseball at a speed of 35 m/s? and an angle of 65 degrees above the horizontal. At the same instant, an outfielder 70 m away begins running away form the batter in the line of the ball's flight, hoping to catch it. How fast must he outfielder run to catch the ball? ignore air...
31. ### A coyote chases a rabbit basic vector problem

A coyote chasing a rabbit is moving 8.00 due east at one moment and 8.80 due south 3.80 later. Find the direction of the coyote’s average acceleration during that time (west of due south)? i found Ax = -2.11 and Ay = -2.32. i used the theta = arctan(Ay/Ax) formula and got 47.7 but that...