​20. A boy standing at the top of a tower of 20 m height drops a stone. Assuming g = 10 m/s² the velocity with which it hits the ground is__________
A. 10.0 m/s
B. 20.0 m/s
C. 40.0 m/s
D. 5.0 m/s
Answer:B
​20. A boy standing at the top of a tower of 20 m height drops a stone. Assuming g = 10 m/s² the velocity with which it hits the ground is__________
A. 10.0 m/s B. 20.0 m/s C. 40.0 m/s D. 5.0 m/s