It is desired that the outer edge of a grinding wheel 9.0 cm in radius move at a rate of 6.0 m/s. Determine the angular speed of the wheel. What length of thread could be wound on the rim of the wheel in 3.0 sec when it is turning at this rate?
tell me if i started off right becuz i...
A 2.0 kg block of wood rests on a tabletop. A 7.0 kg bullet is shot straight up through a hole in the table beneath the block. The bullet lodges in the block, and the block flies 25 cm above the tabletop. How fast was the bullet going initially?
i tried using this formula:
p=...
i think kinetic friction force is 60... or do i subtract 75-60 and that'll give me the kinetic friction??
this is what i did
75-f_{}s=0
f_{}s=75
this is the only thing i can think of
A proton (m=1.67x10^-27 kg) that has a speed of 5.0x10^6 m/s passes through a metal film of thickness 0.010mm and emerges with a speed of 2.0x10^6 m/s. How large an average force opposed its motion through the film??
can anybody give me a clue on where i can start?
ok so what i did was find the normal force of the static friction which i believe was N=mg which is N=20(9.8) and then i did the little \mu=f/N with \mu=75/196
and that found me, what i believe to be the static friction.
Now how do i find kinetic friction coefficient??
a dockworker loading crates on a ship finds that a 20kg. crate, intially at rest on a horizontal surface, requires a 75-N horizontal force to set it in motion. However, after the crate is in motion, a horizontal force of 60-N is required to keep it moving with a constant speed. Find the...