Question

A mechanic strikes a nail with hammer moving with velocity of 20km/s. The hammer comes to rest in 0.2 s after striking the nail. Calculate the acceleration of the nail

Answer 1

Hey friend, here is your answer --

Intial velocity ( u ) = 20 km / s
= Changing km/sec to m/sec
= 20 km / sec * 1000
= 20000 m / sec
Final velocity ( v ) = As hammer is coming to rest so final velocity = 0 m / sec
Time ( t ) = 0.2 sec
Acceleration ( a ) = ?

Using Acceleration formula ::

Acceleration = Final velocity - Initial velocity / Time
a = v - u / t
a = 0 - 20 / 0.2
a = -20 / 0.2
a = -20 / 0.2 * 10/ 10
a = -200 / 2
a = -100 m / sec²

Hence there is a retardation ( negative acceleration ) of 100m/sec² or an acceleration of -100m/sec²

Hope it helps you

Answer 2

V equals to u + at therefore.2 is equals to 20 km per second therefore is equals to 20 km per second. 0.2 = hundred km per second square