A hammer weighing 10 kg falls freely onto the anvil from a height of 1.25 m. Impact force 5.0kN. How long is the impact?

m = 10 kg.

g = 9.8 m / s ^ 2.

h = 1.25 m.

F = 5 kN = 5000 N.

tud -?

Let us find the fall time t and the speed of the hammer at impact V.

h = g * t ^ 2/2.

t = √ (2 * h / g).

t = √ (2 * 1.25 m / 9.8 m / s ^ 2) = 0.5 s.

V = g * t.

V = 9.8 m / s ^ 2 * 0.5 s = 4.9 m / s.

At the beginning of the impact, the hammer has a speed of V = 4.9 m / s, at the end of the impact it has a speed of 0 m / s.

Let’s write 2 Newton’s law for impact: m * a = F.

a = V / tsp.

m * V / tsp = F.

tsp = m * V / F.

tsp = 10 kg * 4.9 m / s / 5000 N = 0.0196 s.

Answer: the impact time is tsp = 0.0196 s.