The discussion revolves around the application of the work formula W=F.d cosƟ in various physics problems, particularly focusing on the angle θ between the force and displacement vectors. Participants are examining inconsistencies in angle usage across different problems.
Some participants have provided insights into the nature of the angles involved, suggesting that the angle may sometimes refer to the angle between the force and the perpendicular to the displacement. There is an ongoing exploration of how to determine the correct angle to use in various scenarios.
Participants note that the angle may not always be explicitly provided and that understanding the geometry of the situation is crucial for applying the work formula correctly. There is an emphasis on the need for diagrams and the properties of right triangles to aid in finding the correct angles.
problem like:Doc Al said:
Note that the angle given is not between F and d, but between F and the perpendicular to d. It's up to you to figure out the correct angle!Sculter said:
Again, the angle given is the angle of the stairs with the horizontal. What you need is the angle between the force (gravity) and the displacement.Sculter said:*a man of mass 70kg. goes upstaris of lenth 50m. calculate the work done if g=10m/s2
-answer W=Fd cosθ, 70x10x50 x cos30
Here they just give you the required angle, so you can just plug it in.Sculter said:
To use the work formula you need the angle between the force and the displacement. Sometimes you'll be given that angle directly; other times you'll have to figure out the correct angle to use.Sculter said:
You are welcome.Sculter said:
Start by drawing yourself a diagram. And use the properties of right triangles. (For example, the two angles of a right triangle are complementary. They add to 90 degrees.)Sculter said: