A0.00545-kg bullet is fired straight up at a falling wooden block that has a mass of 3.08 kg. the bullet has a speed of 720 m/s when it strikes the block. the block originally was dropped from rest from the top of a building and had been falling for a time t when the collision with the bullet occurs. as a result of the collision, the block (with the bullet in it) reverses direction, rises, and comes to a momentary halt at the top of the building. find the time t.

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 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. a) what is the block's initial mechanical energy? 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.

Assume similar data for the motion of the blood in your aorta. estimate how many beats of the heart it will take the blood to get from your heart to your brain. (assume that the distance from your heart to your brain is 30 cm)

Within a pendulum, as potential energy decreases, energy increases. a. heat b. kinetic c. frictional d. gravitational