- #1

Vigorous

- 33

- 3

- Homework Statement
- See the masses in Figure (1) which start out at rest. (i) Find the velocity of the 14 kg mass just before it hits the ground. (ii) Find the maximum height reached by the 8 kg (and don’t worry about hitting the pulley). (iii) Find the fraction of mechanical energy left when the system finally comes to rest.

- Relevant Equations
- 1) Newtons laws

2) Energy Conservation

i) I first analyzed the forces as soon as the 14 Kg is released. The aim of this step is to calculate the work done by the net force acting on the 14 kg mass to determine the change in kinetic energy.

T-14g=-14a

T-8g=8a

T=99.7 N a=6g/22 m/s^2

Since the net force is constant and does not vary with distance

K2-K1=F*distance travelled=-37.418*5=187.1 =1/2mv2^2

K1=0 Since the system starts at rest. solving for v2

v2=5.169 m/s

When the system was at rest, was there an external force pushing down on the 8 kg mass to counter what the tension force wants to do. Similarly, another external force acting on the 14 kg mass to hold it at 5m off the ground. At the point of release, these external forces are removed. I am not sure of my reasoning.

T-14g=-14a

T-8g=8a

T=99.7 N a=6g/22 m/s^2

Since the net force is constant and does not vary with distance

K2-K1=F*distance travelled=-37.418*5=187.1 =1/2mv2^2

K1=0 Since the system starts at rest. solving for v2

v2=5.169 m/s

When the system was at rest, was there an external force pushing down on the 8 kg mass to counter what the tension force wants to do. Similarly, another external force acting on the 14 kg mass to hold it at 5m off the ground. At the point of release, these external forces are removed. I am not sure of my reasoning.