3 In this question use \(g = 9.8 \mathrm {~m} \mathrm {~s} ^ { - 2 }\)
A ball of mass of 0.75 kg is thrown vertically upwards with an initial speed of \(12 \mathrm {~ms} ^ { - 1 }\) The ball is thrown from ground level.
3
- Calculate the initial kinetic energy of the ball.
3
- The maximum height of the ball above the ground is \(h\) metres.
Jeff and Gurjas use an energy method to find \(h\)
Jeff concludes that \(h = 7.3\)
Gurjas concludes that \(h < 7.3\)
Explain the reasoning that they have used, showing any calculations that you make.