Question

A 1.50 kg rock is thrown up into the air from ground level, reaches a maximum height of 7.00 m, then returns to the ground. Calculate the rock's momentum as it strikes the ground

Answer 1

Answer:

17.565 kgm/s

Explanation:

Momentum = mass × velocity

I = mv..................... Equation 1

But we can calculate the value of v  using the equation of motion under gravity.

v² =  u²+2gs............. Equation 2

Where u = initial velocity, s = maximum heigth, g = acceleration due to gravity.

Given: u = 0 m/s (at the maximum heigth), s = 7.0 m.

Constant: g = 9.8 m/s²

Substitute these values into equation 2

v² = 0²+ 2×7×9.8

v² = 137.2

v = √137.2

v = 11.71 m/s.

Also given: m = 1.50 kg

substitute these values into equation 1

Therefore,

I = 1.5×11.71

I = 17.565 kgm/s