Question

Need Help? Read It Talk to Tutor 4. + -12 points SerPSE8 7.P.033.WI. A 3.40-kg object has a velocity (5.20 î - 2.20 )) m/s. (Note: From the definition of the dot product, v2 = 7.7.) (a) What is its kinetic energy at this moment? (b) Find the net work done on the object if its velocity changes to (8.00 +4.00 )) m/s. Need Help? Read It Watch It Talk to a Tutor Corps nainte Drouin is an Type here to search o O DW o

Answer 1

(a) Kinetic energy KE=1/2 m (v.v)

v.v = (5.20*5.20)-(2.20*2.20)= 22.2 (Since i.i=j.j=1, i.j=j.i=0)

KE= (1/2)(3.40)(22.2)=37.74 Joules

(b) From work energy theorem, Work done W= Change in KE = 1/2 m (v₂²-v₁²)

v₂²=v₂.v₂= (8*8)+(4*4) =80 m/s

v₁²=v₁.v₁= (5.20*5.20)-(2.20*2.20) = 22.2 m/s

W=(1/2)(3.4)(80-22.2)= 98.26 Joules