Question

A hammer of mass 1kg strikes on the head of a nail with a velocity 10m/s.It drives the nail 0.1m into a wooden block.Calculate the force applied by the hammer and the time of impact.

Answer 1

we know that

v² - u² = 2as

the deceleration caused will be

a = (v² - u²) / 2s

here

u = 10 m/s

v = 0 m/s

s = 0.1 m

so,

a = (0 - 10²) / 2x0.1

thus,

a = -500 m/s²

.

now,

we also have

v = u + at

the time taken will be

t = (v - u) / a

or

t = (0 - 10) / -500

thus,

t = 0.02s

.

now, the force applied in instant of time will be

I = F.t = ma.t

here, m = mass of hammer = 1kg

= 1 x -500 x 0.02

thus,

I = -10 Ns