Explanation:
The ball is falling down,
At height of 2.1m, there is both potential and kinetic energy with the ball.
the mechanical energy is 172.1J which will be equal to the sum of kinetic and potential energy.
172.1= Ep + Ek
172.1= mgh + 0.5×m×v^2
172.1 =( 7.26 × 9.81 × 2.1 ) + (0.5 × 7.26 × v^2)
172.1 = 149.6 + 3.63v^2
3.63v^2= 22.5
v^2 = 6.198
v= [tex] \sqrt{6.198} [/tex]
v= 2.49
or u can write it 2.5m/s^2
