Aboat floats in a lake. when the boat moves the force of resistance is proportional to the velocity of the boat. initially the boat is at rest. a person walks from the stern to the bow of the boat. what will be the position of the boat long time after the person stopped moving?

Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if λ = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.

What is the final velocity of the initial velocity of 25 and -50?

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?