Question

A ball is thrown upwards. Its height varies
with time as shown in figure. If
acceleration due to gravity is 10 m/s2,
then the height h is (g = 10 m/s2).
Height (m)
In
f(s)
1 2
5 6​

Answer 1

Given: A ball is thrown upwards, acceleration due to gravity is 10 m/s^2.

To find: the height h ?

Solution:

• Now we have given a ball is thrown upwards, acceleration due to gravity is 10 m/s^2.

• Now the velocity at the highest point will be zero.

• So:

                    v = u + at

                    0 = u + (-a)t

                    u = at

• So the time will be 3.5 s as it is the centre position.

                    u = 10 x 3.5 = 35 m/s        .................(i)

• Now s = ut + 1/2(at^2)

• So:

                    y1 = u(1) - 1/2(10)1^2

                    y1 = u - 5

                    y2 = u(2) - 1/2(10)2^2

                    y2 = 2u - 50

• Now h = y2 - y1

                    h = 2u - 50 - u + 5

                    h = u - 45

• Putting i in above equation, we get:

                    h = 35 - 45

                    h = 10 m

Answer:

          So the height is 10 m.