Question

A 12-kg lead brick falls from a height of 1.9 m. (c) The brick falls onto a carpet, 2.0 cm thick. Assuming the force stopping it is constant, find the average force the carpet exerts on the brick.

Answer 1

Answer:

F = -11199.63 N

Explanation:

given,

mass of the brick = 12 Kg

height of the fall, h = 1.9 m

thickness of the carpet = 2 cm = 0.02 m

average force = ?

velocity of brick just before hitting mat

$v = \sqrt{2gh}$

$v =\sqrt{2\times 9.81\times 1.9}$

      v = 6.11 m/s

velocity of brick just before hitting ground= 6.11 m/s

final velocity = 0 m/s

using equation of motion for acceleration calculation.

 v² = u² + 2 a s

 0² = 6.11² + 2x a x 0.02

 $a = -\dfrac{6.11^2}{0.04}$

    a  =-933.3025 m/s²

now, average force is equal to

F = m a

F = 12 x (-933.3025)

F = -11199.63 N

negative sign represent the decelerating force.