An ideal spring is used to fire a 15.0-g block horizontally across a frictionless table top. The spring has a spring constant of 20 N/m and is initially compressed by 7.0 cm. The speed of the block as it leaves the spring is:
i do the following:
energy stored by spring: (kv^2)/2= 0.049...
this was my attempt but I'm not getting the right answer:
ok here is how to do it (i think) both the sphere and the pully will have angular speeds so you can figure out there angular momentum via L = Iw now the change in angular momentum of the system must equate to the change in potential...
A uniform spherical shell of mass, M=4.5 kg and radius R=8.5 cm can rotate about a vertical axis on frictionless bearings. A massless cord passes around the equator of the shell, over a pulley of rotational inertia I=3.0*10^-3 kg*m^2 and radius r=5.0 cm, and is attached to a small object of mass...
okay...is this right so far
i get by combining and rearranging the following new equation:
Cos (theta) + Sin(theta)= 0.003121363m
where m is the mass of the object...what should i do next?
how would i rearrange the first equation to get it interms of mg?
b/c the i have
Tcos(theta) - u(static coefficient)F(normal)=0
force normal does not equal the force of gravity because the force applied on the string is at an angle so i can't just say 'force of gravity=force normal'...
hey
A 1000 kg boat is traveling at 90km/h when its engine is shut off. The magnitude of the frictional force between boat and water is proportional to the speed v of the boat: force of kinetic fricition=70v, where v is in meters per second and the force is in Newtons. Find the time required...
Question: An initially stationary box of sand is to be pulled across a floor by means of a cable in which the tension should not exceed 1100 N. The coefficient of static friction between the box and the floor is 0.35.
a) what should be the angle between the cable and the horizontal in order...