The car observer measured initial energy as 0.5*5*6*6 Joules = 90 J and final energy as 0.5*5*(-3)*(-3) + 0.5*30*(+1.5)*(+1.5) Joules = 56.25J with a loss of Joules. The sidewalk pedestrian observer reported an initial energy of 0.5*5*(+4)*(+4) + 0.5*30*(-2)*(-2) = 100 J and final energy as 0.5*5*(-5)*(-5) + 0.5*30*(-0.5)*（-0.5） = 66.25J with a loss of Joules. The arithmetic showed that the total kinetic energy loss to heat, sound, etc. of the two-object system (impactor-target system) is the s for both observers, just like the exchange impulse of 45 N-sec is the s for both observers.

Oxygen and nutrients are moved through the body by the: a. circulatory system c. lymphatic system b. digestive system d. reproductive system

If a simple machine reduces the strength of a force, what must be increased?

The base of a 50-meter tower is at the origin; the base of a 50-meter tree is at (0, 50, 0). the ground is flat and the z-axis points upward. the following parametric equations describe the motion of six projectiles each launched at time t = 0 in seconds. (i) r (t) = (50 + t2)k (ii) r (t) = 2t2 j + 2t2k (iii) r (t) = 50 i + 50 j + (50 − t2)k (iv) r (t) = 2t j + (50 − t2)k (v) r (t) = (50 − 2t) i + 2t j + (50 − t)k (vi) r (t) = t i + t j + tk (a) which projectile is launched from the top of the tower and goes downward? at time t = , the projectile hits the ground at point (x, y, z) = . (b) which projectile hits the top of the tree?