All Leaving Cert Mathematics posts
• #### HELP WITH QUESTION PLEASE leavingcert16

Can anyone do question 11 on page 400 in active maths book 1? It is about integration, cannot do it at all... :(

1. #### leavingcert16

Raindrops grow as they fall, their surface area increases, and therefore the resistance to their falling increases. A raindrop has an initial downward velocity of 10 m s–1 and its downward acceleration is given by

a(t) = {9 – 0.9t if 0 ≤ t ≤ 10 0 for t > 10

The raindrop is initially 500 m above the ground.

(i) Find the velocity function v(t) of the raindrop after t seconds, 0 ≤ t ≤ 10.

(ii) Find v(10) and hence, write down the speed at which the raindrop hits the ground.

(iii) Find s(t), the distance travelled by the raindrop in t seconds, 0 ≤ t ≤ 10. (iv) How long does it take the raindrop to fall?

yes

3. #### kinger

Integrate a(t) function to find v(t). Sub in 10 in v(t) function for part 2

Integrate v(t) function to find s(t) and go from there. Hope this helps.