The work required to speed up a car from 10 km/h to 20 km/h is 5.0 x 10^3J, what
ID: 2197531 • Letter: T
Question
The work required to speed up a car from 10 km/h to 20 km/h is 5.0 x 10^3J, what would be the work required to increase the car's speed from 20 km/h to 30 km/h? Please explain how to get the mass.Explanation / Answer
By work energy theorem:- =>W = ?KE =>5000 = 1/2 x m x [(20 x 1000/3600)^2 - (10 x 1000/3600)^2] =>m = 432 kg 2nd condition:- =>W = ?KE =>W = 1/2 x m x [(vf)^2 - (vi)^2] =>W = 1/2 x 432 x [(30 x 1000/3600)^2 - (20 x 1000/3600)^2] =>W = 8333.33 J =>W = 8.3 x 10^3 J work is equal to kinetic energy and potential energy (which is zero) we know 1/2mvf^2-1/2mvi^2=5*10^3 J=m(1/2vf^2-1/2vi^2) so if vf=20 km/h (convert to m/s) and vi=10 km/h we find m about 432 then we use the same equation but vf=30km/h and vi=20km/h 8333J about By work energy theorem:- =>W = ?KE =5000 = 1/2 x m x [(20 x 1000/3600)^2 - (10 x 1000/3600)^2] =m = 432 kg =W = KE =W = 1/2 x m x [(vf)^2 - (vi)^2] =W = 1/2 x 432 x [(30 x 1000/3600)^2 - (20 x 1000/3600)^2] =W = 8333.33 J =W = 8.3 x 10^3 J =8333J
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