Question

(a) A basket is thrown along perfectly vertical line downwards with an initial speed of 13 meters per second from the height of 34.66 m above the ground. (i) How long will it take the basket to hit the ground? (ii) What will be the speed of the basket upon impact?
(b) A key is accidentally dropped by a tourist into a river from a bridge 43.9 m above the water followed by a stone which is thrown down by a kid 2 second after the key starts falling. The key and the stone strike the water at the same instant. What is the initial velocity of the stone?

Answer 1

Answer:

B)

The value of t = 3 sec

u = 39 m/s

Explanation:

B)

We will use the basic equation of motions to solve the problem. Consider the below equation of motion

s = ut + 1/2 gt^2

Where u is the initial velocity.

For the case of key,

s = 43.9m

u = 0

Putting the values

43.9 = 0 x 1/2 (9.8 ) t^2

The value of t = 3 sec

Now the stone is thrown after 2 secs, which means it takes only 1 sec to cover the 43.9 distance

43.9 = u ( 1) + 1/2 (9.8) (1^2)

u = 39 m/s