1. a fixed pulley is a machine that increases the effort force.
true
false

2. a movable pulley is fixed at all points.
true
false

3. a block and tackle consists of both movable and fixed pulleys.
true
false

4. a lever is a bar that can pivot on a fixed point.
true
false

5. a wedge is a machine that changes the direction of the force.
true
false

Match the atomic particles with their characteristics. 1. made of two protons and two neutrons neutron 2. similar to an electron; positive charge neutrino 3. orbits nucleus; negative charge positron 4. bundle of energy; zero charge proton 5. found in nucleus; positive charge meson 6. very unstable; +, -, or zero charge gamma 7. found in nucleus; zero charge electron 8. negative particle; negative charge beta 9. atomic energy converted to mass alpha

The momentum of an isolated system is conserved a) only in inelastic collisions. b) only in elastic collisions. c) in both elastic and inelastic collisions

What is created when solids,liquids,an gases mix with one another