James 27 Feb 2017 - 1

Question

A body is thrown vertically up from the ground with an initial speed u and it reaches the maximum height h at time t0.

What is the height it reaches at ½ t0?


Answer

We first define the upwards direction as positive.

When the body reaches the maximum height, the speed of the body is 0.

Knowing this, we can find expressions for h and t0. The acceleration of the body is taken to be 10 ms-2 downwards. Since we define upwards to be positive, the acceleleration will be -10 ms-2.

When the time is ½ t0,

Now that we know the speed at ½ t0, we can find the height travelled by the body.