+12 an as physics student plans to enter for the high jump event at the school sports. she estimates that, if she has a chance of winning, she will have to raise her centre of gravity of mass by 1.6 to clear the bar. she will also have to move her centre of mass horizontally at a speed of 0.8 ms at the top of her jump in order to roll over the bar.the students mass is 75kg. estimate the total energy required to raise her centre of mass and roll over the bar
+394 Vertically elevating a mass of 75Kg to 1.6m through a gravity field of 9.8m/s2 requires a kinetic energy of
KE = m *g * h
75kg *(9.8m/s2) * 1.6m =1176 Joules
The energy required to accelerate a mass of 75kg to a velocity of 0.8m/s is
KE= 0.5(m)*v2
0.5(75kg) * (0.8m/s)2 = 24 Joules
Total energy is the sum of these: 1176 + 24 = 1200 Joules
Extra energy will be required for overcoming wind resistance, and for curving and unfolding herself over the bar. The wind resistance should be easy to calculate. The rest not so much.
_7UP_
+394 Vertically elevating a mass of 75Kg to 1.6m through a gravity field of 9.8m/s2 requires a kinetic energy of
KE = m *g * h
75kg *(9.8m/s2) * 1.6m =1176 Joules
The energy required to accelerate a mass of 75kg to a velocity of 0.8m/s is
KE= 0.5(m)*v2
0.5(75kg) * (0.8m/s)2 = 24 Joules
Total energy is the sum of these: 1176 + 24 = 1200 Joules
Extra energy will be required for overcoming wind resistance, and for curving and unfolding herself over the bar. The wind resistance should be easy to calculate. The rest not so much.
_7UP_
