Question

A kangaroo Can jump 2.5m vertically. What must be initial velocity of kangaroo.

Answer 1

V^2=u^2+2as
v=0( at topmost point final velocity=0)
a=-9.8m/s^2
h=2.5m

0=u^2+2(-9.8)(2.5)
U^2=99
U=10m/s(approx).

Answer 2

Answer:

The initial velocity of the kangaroo must be 7 m/s.

Explanation:

a = 9.8 m/s²

s = 2.5 m

v = 0 m/s

v² = u² + 2as

=> (0)² = u² + 2 * (-9.8) * 2.5

=> 0 = u² - 5 * 9.8

=> 0 = u² - 49

=> u² = 0 + 49

=> u² = 49

=> u = 7 m/s

So,

The initial velocity of the kangaroo must be 7 m/s.

Here, negative sign of acceleration shows that it is in the opposite direction of the velocity.