View Full Version : Right direction physics
Maria A Gonzale
Sep 29, 2008, 08:00 PM
If 460 kg bear grasping a vertical tree slides down at constant velocity. With acceleration of gravity being 10 m/s^2. What is the fraction force that acts on the bear?
Will I use F=ma, so 460 times 10?
Am I in the right direction
ebaines
Sep 30, 2008, 05:39 AM
Yes, you are on the right track. If the bear slides at constanjt velocity, then you know that its acceleration is 0. Hence F = 0. This means that the bear's weight is exactly counter-acted by the friction of the bear's claws against the tree. Can you take it from here?
Maria A Gonzale
Sep 30, 2008, 02:06 PM
So will the frictional force be 460N
ebaines
Sep 30, 2008, 02:16 PM
Not quite. The bear's mass is 460 kg, but his weight is a force, given in Newtons. If you know an object's mass, its weight under earth gravity is mg.
Maria A Gonzale
Oct 1, 2008, 01:32 PM
Okay I am confused, so exactly what am I doing wrong...
ebaines
Oct 1, 2008, 03:55 PM
okay i am confused, so exactly what am i doing wrong...
Well... a 460Kg bear has a weight of 460kg * 10m/s^2 = 4600 Newtons.