The kinetic energy of a baseball is doubled by changing the speed of the baseball. By what factor has its speed changed? √ 2 v i n i t i a l 2 vinitial 2 v i n i t i a l 2vinitial 4 v i n i t i a l 4vinitial 1 2 v i n i t i a l 12vinitial 1 4 v i n i t i a l

1/√2

Explanation:

Kinetic energy of a body is expressed as

KE = 1/2mv²

If it's KE is doubled

2KE = 1/2mv1² where v1 is the new speed when the kinetic energy is doubled

To know the value of the amount the velocity has changed, we will divide both equations

2KE/KE = (1/2mv²)/(1/2mv1²)

2 = v²/v1²

(v/v1)² = 2

v/v1 = √2

v1 = v/√2

v1 = 1/√2 × v

The new velocity has changed by

1/√2vinitial

i think it’s a. this is because if they measured the mass of something with a mass of 150g, then their final answer would have to be approximately 150g. though all of their answers are almost 150, rosa and tran have the closest answers (or the exact answer) to the accurate one.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.