- #1

Grinter1

- 5

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A pile-driver hammer of mass 150kg falls freely a distance of 5m to strike a pile of mass 400kg and drives it 75mm in the ground. The hammer doesn't rebound when driving the pile. Calculate the average resistance of the ground. You are required to solve this problem by:

(a)By making use of the principle of conservation of momentum and D'lamberts principle

2. Homework Equations

v=u+at

v2(squared)=u2(squared)+2as

S=ut+0.5at2(squared)

f=m*a

3. The Attempt at a Solution

a)

Hammer mass=150kg

Falls freely= gravity = 9.81

Distance= 5m

pile mass =400kg

depth= 75mm= 0.075m

no rebound

Average resistance= ?

M1*U1+M2*U1=M3*V1

(150*9.81)+(400*0)=1471.5 m/s

a=v(squared)-U(squared)/2*5

a= 0.981

f=m*a

f=147.15

FR=f-m*a-m*g

FR= -5395.5