two small blocks are connected by a string of constant length 4h and negligible

Question

two small blocks are connected by a string of constant length 4h and negligible mass. Block A has a mass of 3m and is placed on a smooth, frictionless tabletop. Block B has a mass of 2m and hangs over the edge of the table. The tabletop is a distance 2h above the floor. Block B is the released from rest at a distance h above the floor at time t = 0.

B) As block B descends, which block has a greater net force acting on it? please explain

C) Block B strikes the floor and does not bounce. Determine the time t1 at which block B strikes the floor.

D) Describe the motion of block A from time t=0 tot the time t1 when block B strikes the floor.

E ) Describe the motion of block A from the time t1 when block B strikes the floor to the time t2 when block A leaves the table.

F ) Determine the speed with which block A strikes the floor.

Please explain how you get your answers so I can understand the process, thank you!

Explanation / Answer

A) net force on Block B is Fnet = mg-T = ma

net force on block A is Fnet = T = ma

then mg-ma = ma

2ma = mg

a = 9/2 = 9.81/2 = 4.905 m/s^2

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B) using s = ut +(0.5*a*t^2)

h = (0.5*4.905*t^2)

t = sqrt( h/(0.5*4.905)) = 0.638*h

C) u = 0 m/s

a = 4.905 m/s^2

t= 0.638 h

distance travelled is S = (ut)+(0.5*a*t^2)

S = 0.5*4.905*0.638*0.638*h^2 = h^2

d) the distance travelled by A from the time block B strikes the floor to the time block A leaves the table is 3h-h^2

F) at which whic it was leaving the table is u = sqrt(2*(g/2)*3h) = sqrt(3*g*h)

then at the floor is v = u^2 - (2*(g/2)*2h) = 3gh- 3gh = gh

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