Which two forces act directly on objects that are unable to be viewed by the unaided eye?

electromagnetic and strong

gravitational and electromagnetic

strong and weak

weak and gravitational

Which of the following is an example of weathering, but not of erosion? A. wind blows sand down a beach B. freezing water breaks apart a rock C. small rocks slide down a hill D. a river carries sediment to the ocean

Two powerboats are about to cross paths. what should the boat on the starboard (right do?

Explain how a balloon can become positively charged when rubbed with a cloth

Write an expression for the magnitude of the normal force, fn, acting on the block, in terms of f2 and the other variables of the problem. assume that the surface it rests on is rigid.

What is the pH range of an acid? 0 - 6 6 - 8 8 - 14 0 - 14

Volcanic eruption affects water drainage but what may that result in

The probability that a battery will last 10 hr or more is 0.8, and the probability that it will last 15 hr or more is 0.11. Given that a battery has lasted 10 hr, find the probability that it will last 15 hr or more

What is the sum of 9260 and 3240? Express your answer numerically to at least three significant figures.

What could you do if the plant is placed in your community and later leads to pollution beyond the amounts allowed by the EPA?

The friends now feel ready to try a problem. Suppose an Atwood machine has a mass of m1 = 2.5 kg and another mass of m2 = 8.5 kg hanging on opposite sides of the pulley. Assume the pulley is massless and frictionless, and the cord is ideal.