Question

A stone dropped from the top of a tower travels $\frac{5}{9}$th of the height of tower during the last second of fall. Height of the tower is: (take g = $10m/s^2$)

• A. 52 m
• B. 36 m
• C. 45 m
• D. 78 m

Answer 1

The correct option is B 36 m

As g is given to be $10m/s^2$ the stones speed will increase by 10 m/s for every second of fall, therefore, the distance traveled at any given time will be an integral multiple of 10, let's look at the options,

a) 52 m $\frac{(52\times 5)}{9}$ = 28.88 m
b) 36 m $\frac{(36\times 5)}{9}$ = 20 m
c) 45 m $\frac{(45\times 5)}{9}$ = 25 m
d) 78 m $\frac{(78\times 5)}{9}$ = 43.33 m