26. a 40 kg boy jumps from a height of 4m onto a plate-form mounted on springs. as the
spring compress, the plate-form is pushed down a maximum distance of 0.2 cm below its
initial position, and it then rebounds. what is the loss in potential energy by the boy?
a. 800j
b. 1080j
c. 1600j
d. 1680 j

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island

An ionic compound can conduct electricity when a it is dissolved in water b its crystals are ground into powder c it is in solid form d it is heated to just below its melting point

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.