# Posts by HELP !

Total # Posts: 7

Physics
An image of the moon is focused onto a screen using a converging lens of focal length f= 35.3 cm. The diameter of the moon is 3.48×106 m, and its mean distance from the earth is 3.85×108 m. What is the diameter of the moon's image?

physics
Block A (60 N) and block B (40 N) are connected by a massless cord and are AT REST. Given ìs = 0.8. The friction on A is : 1. 40 N 2. 0 N 3. 24 N 4. 48 N 5. 20 N 6. 60 N 7. 16 N

physics
Block A (70 N) and block B (21 N) are connected by a massless cord and are at rest. Given ìs = 0.8. What is friction A ?

physics
A 95 N block rests on a table. The sus- pended mass has a weight of 22 N. What frictional force is required to keep the blocks from moving? Answer in units of N.

College Chemistry
How fast must a 138 g baseball travel in order to have a de Broglie wavelength that is equal to that of an x-ray photon with = 100. pm?

Chemistry
58970 ? But, it has to be 3 significant figures, right ? So, would it be 5.90e4

Chemistry
Organic hydrogenation reactions, in which H2 and an "unsaturated" organic compound combine, are used in the food, fuel, and polymer industries. In the simplest case, ethene (C2H4) and H2 form ethane (C2H6). If 124 kJ is given off per mole of C2H4 reacting, how much ...