Question

A Ball is dropped from the window which is 8 metre above the ground the initial velocity of ball was 4 metre per second find the time which it take to reach the ground​?

Answer 1

Answer:

0.92 seconds

Explanation:

Given :

• Initial velocity = u = 4 m/s

• Distance travelled = s = 8 metres

• Acceleration due to gravity = a = 10 m/s²

To find :

• Time taken by the ball to reach the ground

Using the second equation of motion :

S=ut+½×at²

8=4×t+½×10×t²

8=4t+5t²

5t²+4t-8=0

By solving the above quadratic equation, T = 0.92 seconds

The time taken to reach the ground is 0.o2 seconds

Answer 2

Given:-

• Height (s) of the ball when it is dropped =8m

• Initial velocity (u) of ball = 4 m/s

• Acceleration (a) due to gravity = 9.8 m/s²

• Final velocity (v) of the ball = 0 m/s

To Find:-

• Time taken (t) by the ball to reach the ground .

Solution:-

We have to calculate the time taken by the ball to reach the ground.

So, By using 2nd equation of motion

➦ s = ut + 1/2at²

Putting all the values which is given above.

8 = 4 ×t +1/2 ×9.8 × t²

8 = 4t + 4.9 × t²

8 -4t -4.9t² = 0

By Solving this quadratic equation we get Time = 0.933 second.

∴ Time taken by ball to reach on the ground is 0.933 s.