tyrannt

Not quite. there are two types of friction. static and kinetic. kinetic is usually lesser in magnitude than static. Static friction <= coefficient * (mass * gravity) the mass * gravity is refered to as the normal force, which is the force which the object applies on the ground. The less than or equal to means that this force will change in order to rival whatever force is trying to move it until the moving force becomes greater than the maximum value. At this point the object will begin to move. Merged post follows: Consecutive posts mergedthink about this. the radius is the distance from the center right? therefore, the problem does tell us the radius by stating the penny's distance from the center of the circle.

Ok, so wait, the static friction you reported. Is that the coefficient of static friction or the overall force of static friction? If it is the coeffient, you need to find the static frictional force which is Static Fricion (less than or equal to) coefficient * normal force. Then you would need to find out how much centripital force is being applied to the penny. Centripital force = (mass)*(velocity^2)/radius If the centripital force is greater then the static frictional force, the penny will slide. It is important to note that the forces act in opposite directions.

It is important to remember, and many people look this over, electrolysis for splitting water into hydrogen and oxygen takes a lot of energy. That is why we don't have a lot of hydrogen cars yet. It would be more efficient to just have electric cars. This can be proven by taking a battery and observing what volume of gas it produces in relation to the total energy the battery exerts. Then, compare this value to the power production capability to the space station and how much oxygen is consumed by the people onboard.

You should go for it but remember, in terms of job openings, bio is somewhat narrow. At my school, bio majors have a hard time finding internships and such but if you really like bio, go for it for sure.