• Support PF! Buy your school textbooks, materials and every day products via PF Here!

Physics Puzzler!

  • Thread starter paigegail
  • Start date
22
0
HELP!!!!! I am in grade 12 physics and my teacher gave us a puzzler for the weekend. I need serious help with it and all of my classmates cant figure it out either! The question is :

A 10.8 kg box is 5.0 m from the edge of a 12.96 m high cliff. Bob pushes the box over the edge of the cliff by applying a constant horizontal force to it until the box goes over the edge. The force of friction on the box is 49.0 N and the box lands 7.5 m from the base of the cliff. How much force did Bob apply to the box while he was pushing?

What do I do and can someone show me how to solve it?
 
22
0
A 10.8 kg box is 5.0 m from the edge of a 12.96 m high cliff. Bob pushes the box over the edge of the cliff by applying a constant horizontal force to it until the box goes over the edge. The force of friction on the box is 49.0 N and the box lands 7.5 m from the base of the cliff. How much force did Bob apply to the box while he was pushing?

If v is the (horiz.) velocity at push-off and t the time of fall;
vt = 7.5; (1/2) gt^2 = 12.96; Find v.
Total work done by all forces till push-off,
(F-49)5 = Kinetic energy at push-off = (1/2) (10.8) v^2
 

Related Threads for: Physics Puzzler!

Replies
3
Views
1K
  • Posted
Replies
1
Views
1K
  • Posted
Replies
10
Views
1K
  • Posted
Replies
19
Views
1K
Replies
13
Views
2K
Replies
0
Views
934
Replies
1
Views
1K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top