its mass is 950 kg. find it's ke. Oct 22 | Sierra from Champion, PA | 3 Answers | 0 Votes Mark favorite Subscribe Comment
KE = ½mv², where v is in m/s. v= 100 km/h = 27.8 m/s KE = ½(950kg)(27.8m/s)²=367,000 J (I'm assuming 3 significant digits, though it could be just 2 or 1.) Oct 22 | Andre W. Comment
Hey Sierra -- 950kg moving 100km/hr ... V is 100m/3.6s ... KE= 0.5mV*V ... KE= 0.5(950)100(100)/(3.6*3.6) ~ 480E4/(36*0.36) ~ 40E4/(3*0.36) ~ 400kJ - 8% ... KE ~ 400 - 32 ~ 370kJ ... Regards :) Oct 23 | Brad M. Comment
Hi Sierra; Good to hear from you again. I am assuming that ke is Kinetic Energy. ke=(1/2)mv^{2} ke=(1/2)(950 kg)(100 km/hour)^{2} ke=(1/2)(950 kg)(10000 km^{2}/hour^{2}) ke=4750000 kg-km^{2}/hour^{2} Oct 22 | Vivian L. Comment Comments ke=4750000 kg-km^{2}/hour^{2} Do you need to convert to seconds?... ke=[4750000 kg-km^{2}/hour^{2}][(1 hour)^{2}/(360 sec)^{2}] ke=13194 kg-km^{2}/sec^{2} Do you need to convert to meters?... ke=[13194 kg-km^{2}/sec^{2]}[(1000 m)^{2}/(1 km)^{2}] ke=1319400 kg-m^{2}/sec^{2} Oct 22 | Vivian L. Yes, you should convert to meters/second, because a joule is defined as 1 J = 1 kg *m²/s² Oct 22 | Andre W. Good point! But she did not say she need Standard Units. Oct 22 | Vivian L. Numerical answer only in mj to 3 decimal places Oct 22 | Sierra from Champion, PA Then please use Andre's answer. I apologize if I caused any confusion. Oct 22 | Vivian L. 0.367 MJ Oct 22 | Andre W. You're doing great, Vivian! And remember, 1 hour = 3600 seconds. :) Oct 22 | Andre W. Comment
ke=4750000 kg-km^{2}/hour^{2} Do you need to convert to seconds?... ke=[4750000 kg-km^{2}/hour^{2}][(1 hour)^{2}/(360 sec)^{2}] ke=13194 kg-km^{2}/sec^{2} Do you need to convert to meters?... ke=[13194 kg-km^{2}/sec^{2]}[(1000 m)^{2}/(1 km)^{2}] ke=1319400 kg-m^{2}/sec^{2} Oct 22 | Vivian L.
Yes, you should convert to meters/second, because a joule is defined as 1 J = 1 kg *m²/s² Oct 22 | Andre W.
Comments