Question

Need help with this question. Thirty points.

Answer 1

`1)\\\\\text{Kinetic energy,}\\\\E_k = \frac 12 mv^2 \\\\\implies m = (2E_k)/(v^2) = (2* 4500)/(30^2)=10~ kg\\ \\2)\\\\\text{Kinetic energy,}\\\\E_k = \frac 12mv^2 \\\\\implies v^2 = \frac{2E_k}m\\\\\implies v = \sqrt{(2E_k)/(m)}=\sqrt{(2 * 320)/((20)/(9.8))}= 17.709 ~ ms^(-1)\\\\3)\\\\\text{Kinetic energy,}\\\\E_k=\frac 12 mv^2=\frac 12 * 50 * 10^2=2500 ~J\\\\\\`

`4)\\\\\text{Potential energy,}\\\\E_p =mgh = 5* 9.8* 1.5 = 73.5 ~J`