453,793 views
5 votes
5 votes
A mass of 50 kg is then dropped from 20m . What is its speed as it hits the ground?

User Djschwartz
by
2.6k points

1 Answer

12 votes
12 votes

Statement:

A mass of 50 kg is dropped from 20m.

To find out:

The speed of the ball as it hits the ground.

Solution:

  • Mass (m) = 50 Kg
  • Height (h) = 20 m
  • Initial velocity (u) = 0 m/s [The ball was at rest]
  • Acceleration due to gravity (g) = 10 m/s^2
  • Let the speed of the ball as it hits the ground be v.
  • We know the equation of motion for a freely falling body,
  • v^2 = u^2 + 2gh
  • Putting the values in the above equation, we get
  • v^2 = (0)^2 + 2(10)(20)
  • or, v^2 = 400
  • or, v = √400
  • or, v = 20 m/s

Answer:

The speed of the ball as it hits the ground is 20 m/s.

Hope you could understand.

If you have any query, feel free to ask.

User Sandeep Rajoria
by
3.2k points