Which blood vessels carry oxygen and nutrients directly to the individual cells in tissues and organs?
a. veins
b. arteries
c. capillaries
d. venules

how do capillaries differ in structure from arteries and veins?

a. capillaries have smoother muscle tissue than veins.
b. capillaries appear to have a larger diameter than veins
c. capillaries have valves which are absent in arteries.
d. capillaries are only one cell thick and lack smooth muscle.

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 790 n/m. it is initially at rest on an inclined plane that is at an angle of 28 degrees with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is k = 0.14. in the initial position, where the spring is compressed by a distance of a = 0.18 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

You throw a baseball directly upward at time =0 at an initial speed of 14.9 m/s. what is the maximum height the ball reaches above where it leaves your hand? ignore air resistance and take =9.80 m/s2.