a 2 kg rock is dropped from the top of a 30 m High building calculate the ball at the time that it strikes the ground

48.54kgm/s

Explanation:

Momentum is defined as the product of mass and velocity of an object. Mathematically,

Momentum = Mass*velocity

Given mass = 2kg

Velocity of the body as it strikes the ground can be gotten using the equation of motion v² = u²+2as where;

v = final velocity of the body

u = initial velocity of the body = 0m/s

a = g = acceleration due to gravity

S = h = height covered by the rock

The equation will then become

v² = u²+2gh

v² = 0²+2 (9.82) (30)

v² = 589.2

v = √589.2

v = 24.27m/s

the momentum of the ball at the time that it strikes the ground = mass * velocity

= 2*24.27

= 48.54kgm/s

First you find the final velocity which is the velocity when the ball hots the ground: v^2 = v0^2 + 2ad. We know acceleration is - 9.8 and d is - 30 and v0 is 0 so all we do is plug everything to find v = ==> v = 24.25

Now we find momentum which is mv so momentum is 2 times the velocity

Momentum = 48.5 kg-m/s