For a freely falling body, the distance traveled in time
t is given by the equation:
s=ut+21​gt2where:
-
u is the initial velocity (which is 0 for a freely falling body),
-
g is the acceleration due to gravity (
g≈9.8m/s2),
-
t is the time.
In the first 4 seconds, the body travels a distance of 80 m. Using the formula, we can write:
80=0+21​g(4)2 80=21​g⋅16 g=1680×2​=10m/s2So, the value of
g is approximately
10m/s2.
Now, in the next 4 seconds, the body continues to fall, and the distance covered in the next 4 seconds can be calculated as follows:
The total distance traveled in 8 seconds:
s=21​g(8)2=21​×10×64=320mThe distance covered in the next 4 seconds is the difference between the total distance covered in 8 seconds and the distance covered in the first 4 seconds:
Distanceinnext4seconds=320−80=240mThus, the correct answer is option (B), 240 m. Quick Tip: In problems involving freely falling bodies, use the kinematic equation
s=ut+21​gt2 to find the distance traveled over a given time. Ensure to use the correct value for acceleration due to gravity.