Question

An object of mass 10 kg is allowed to fall to the ground from a height of 20 m. How long will it take to reach the ground? (g-10 ms-2)

• A. 1s
• B. 2 s
• C. 3s
• D. 4s

Answer 1

Answer:

B. 2 s

To find the time it takes for the object to reach the ground, we can use the equation:

h = ut + (1/2)gt^2

where:
h = height (20 m)
u = initial velocity (0 m/s, since it's dropped from rest)
g = acceleration due to gravity (10 m/s^2)
t = time

Rearranging the equation to solve for t:

t = √(2h/g)

Plugging in the values:

t = √(2 x 20 m / 10 m/s^2)
= √(4 s^2)
= 2 s

The final answer is: 2 seconds