A woman drops a rock from a bridge to the water 17.5 m below. with what speed does the rock strike the water? a. 0 m/s
b. 18.5 m/s
c. 171m/s
d. 9.8 m/s
e. 17.5 m/s

An object is dropped from a tower, 400 ft above the ground. the object's height above ground t seconds after the fall is s(t)equals400 minus 16 t squared. determine the velocity and acceleration of the object the moment it reaches the ground. the velocity of the object the moment it reaches the ground is nothing ft/s.

20) what is a magnetic field? 21) in which direction do magnetic field lines always point? 22) sketch a diagram showing how a plotting compass points around a 23) name two magnetic poles that will: a) attract each other b) repel each other. 24) explain why you can use a compass to navigate. 25) what's an electromagnet? 26) list two ways to increase the strength of an electromagnet. 27) the wire in a simple motor feels a force when a current flows through it. why is this? i need answers to check mine

18. a 6.7 kg object moves with a velocity of 8 m/s. what's its kinetic energy? a. 26.8 j b. 167.5 j c. 53.6 j d. 214.4 j