Acceleration due to freefall

1
Acceleration due to freefall

• The uniform acceleration formulae can be used
  when dealing with free fall under gravity.
  Under such circumstances the acceleration due to
  gravity is approximately 9.8 m/s2. (This value
  is often taken to be 10 m/s2 for convenience)

2
Example A brick is thrown vertically downwards
from the top of a building and has an initial
velocity of 1.5m/s. If the height of the building
is 20m, taking g 10 m/s2 find a) The velocity
with which the brick hits the ground, b) The time
taken for the brick to fall.
3
Example A ball is thrown vertically upwards with
a speed of 14.7 m/s from a platform 19.6m above
level ground. Calculate, a) The time taken for
the ball to reach the ground b) The speed of the
ball when it reaches the ground.
4
Example A particle is projected vertically
upwards with a speed of 34.3 m/s. Find how long
after projection the particle is a) At its
maximum height b) At a height of 49m above the
point of projection for (i) the first time (ii)
the second time.
5
Example A ball is thrown vertically upwards with
a velocity of 34.3m/s. Find how long after
projection the particle is at a height of 49m
above the point of projection for a) The first
time b) the second time.
6

• 1.A level past paper question
• A ball is thrown vertically upwards from the
  ground with initial speed 11.2 m/s.
• Find the greatest height reached by the ball.
• Calculate the length of time the ball is more
  than 2.8m above the ground.
• State one assumption you have made in your
  solution of the problem.