Today in physics we worked on the first two problems from the 'net force particle model worksheet 2'.

1. For the first problem, the down arrow exerts 46,000 N since the helicopter weighs 4,600 kg. The down arrow is the force of gravity from the earth on the helicopter. Next the acceleration needs to be calculated.

(2.0m/s2)X(4600kg)=9200 N

Now this unbalanced forced needs to be added to 46,000 N since this is the amount of lift force the helicopter would need to hover in midair.

46,000N + 9200N= 55,200 N of lift force from the propellers on the helicopter.

2. Since the bag weighs 20kg the force of gravity from earth on the bag is 200N. Now the unbalanced force from the acceleration of the lift needs to be calculated.

(5.0m/s2)X(20kg)=100 N

In order for the hand to hold the bag in midair, the hand form the person applies 200N of force on the bag. This force is added to the unbalanced for to find the force the hand pulls up with.

200N +100N = 300N

Since the forces are unbalanced and the force from the pull of the hand exceeds 250N, the bag breaks.