(a) A 750 kg automobile is moving at 20m/s at a height of 5m above the bottom of
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Question
(a) A 750 kg automobile is moving at 20m/s at a height of 5m above the bottom of a hill when it runs out of gasoline. The car coasts down the hill and then continues coating, up the other side until it comes to rest. Ignoring the frictional forces and air resistances, Mull is the value of h, the highest position the car reaches above the bottom of the hill? (b) A projectile with mass 500 kg is launched straight up from the Earth's surface. What magnitude of initial KE enables the projectile to reach a maximum height of 100 m?Explanation / Answer
A) applying law of conservation of energy
0.5*m*u^2 + (m*g*h1) = 0.5*m*g*h2
(0.5*750*20*20)+(750*9.81*5) = 0.5*9.81*750*h2
h2 = h = 50.77 m
B) initial KE = m*g*h = 500*9.81*100 = 490500 J
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