Science Check
posted by Abby on .
1)Two balls having the same mass of 1 kg roll toward each other, each moving at the same speed of 1 m/s. What is the combinded momentum?
Would it be 0 kg m/s
2)A 30 kg girl and a 25kg boy face each other on friction free roller blades. The girl pushes the boy who moves away at 1 m/s. The girls speed is?
Would it be .45
3)The power extended when a 10 N barbell is raised 2.0 m in 2 s is _____ watts
would it be 40?
4)Car A travels for times as fast as Car B. When braking to a stop Car A skids____ times as far as car B.
16?
(1) yes
(2) no. 30*Vgirl = 25*Vboy
Solve for Vgirl when Vboy = 1
(3) no. DIVIDE the work by the time
(4) yes. 4^2 = 16 Do you know why the skid is proportional to the square of speed? It has to do with kinetic energy

would it be 55