Work done by gravity on a car rolling down a hill

Click For Summary
The discussion centers on calculating work done by gravity on a car rolling down a hill, with a focus on the formula E = F x cos(θ). A participant mentions obtaining 243 kJ but questions the values used for force (F), distance (x), and angle (θ). The conversation suggests that using the work-energy principle, W = ΔE_P, is more appropriate for this scenario than the traditional formula. Additionally, there is a query about the specific distance represented by 50 cos(8°) m in the context of the problem. The thread emphasizes the importance of correctly applying the relevant formulas to accurately determine the work done by gravity.
physicsmaster123
Messages
3
Reaction score
0
Thread moved from the technical forums to the schoolwork forums
I tried E =Fxcos0 but only ended up with 243kJ
1694284850662.png
 
Last edited by a moderator:
Physics news on Phys.org
What values of ##F##, ##x##, and ##\theta## did you use and why?
 
Hint: What is the textbook definition of ##\theta## in the formula you stated?
 
Last edited:
physicsmaster123 said:
I tried E =Fxcos0 but only ended up with 243kJ
What distance in the diagram is ##50\cos(8°)##m?
 
Specific to this exercise, ##W=\Delta E_P## is a better fit than ##W=Fd\cos \theta##
 

Thread 'Magnitude of buoyant force in fluids of different densities'

The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?
View full post »

Similar threads

Combined Rotation and Translation of a Rectangular Plate
  • · Replies 9 ·
Replies
9
Views
2K
A block dropping onto a spring system
  • · Replies 58 ·
2
Replies
58
Views
3K
Kinetic Energy of a Cylinder Rolling Without Slipping
  • · Replies 21 ·
Replies
21
Views
5K
Final velocity of a car rolling down a ramp using energy
  • · Replies 1 ·
Replies
1
Views
3K
Why Does a Car Accelerate When Rolling Down a Hill?
  • · Replies 11 ·
Replies
11
Views
3K
Forces involved in principle of virtual work
  • · Replies 2 ·
Replies
2
Views
816
Why is the direction of kinetic/static friction up a ramp?
  • · Replies 7 ·
Replies
7
Views
1K
A cylinder of snow rolls down a hill gathering more snow -- calculate its speed
  • · Replies 39 ·
2
Replies
39
Views
3K
Work & Energy (Question on Classical Mechanics/Slope based Problems)
  • · Replies 7 ·
Replies
7
Views
2K
Thermodynamic Work vs Mechanical Work
  • · Replies 3 ·
Replies
3
Views
1K