Discuss Ian's answer to: A Real hard Physics Problem

Answers only work once. Try to learn the methods. You probably know the formula Kinetic energy K = (1/2)mv^2 The answer is in Joules if the mass in kg and speed is in metres per second. This really is not too hard. Try not to give up so easily. The only difficulty is that the speed is given as 110 km/hr 110 km is 110,000 metres 1 hour is 3600 seconds You knew that. So, 110 km/hr is 110,000 metres/3600 seconds = 275/9 metres /sec Now just put m = 1500 kg and v = 275/9 metres /sec into the equation. K = (1/2)*1500*(275/9)^2 Now let a calculator take the strain. K = 700231.48 Joules In round figures, just over 700 kiloJoules Read this through until you feel you could do another one like it in an exam. Regards - Ian