Aspool is placed on table top. the static friction coefficient between the table top and the spool is high.
part (a) if the string is pulled out over the bottom of the axle as shown, in which direction will the spool roll?
multiplechoice :
1) in the same direction as the applied force.
2) it depends on how much force is applied.
3) it will stay in one place and spin.
4) in the opposite direction of the applied force.

In a system, when potential energy decreases, then entropy also decreases. true false

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?

Mixing salt in water is an example of physical change