Which is the best example of a non-inertial frame of reference? (1 point) A. a roller coaster maintaining its speed as it curves around a bend
B. a falling feather in which the upward force due to air resistance equals the force of gravity
C. a spaceship traveling at 947 m/s with its engines off
D. a boat at rest on calm water

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.

If the speed of a particle triples ,by what factor does its kinetic energy increase?

Brutus, the dog, is pulling a bone to the left with a force of 20 n. lassie, another dog, is pulling a bone to the right with a force of 18n. what is the net force? a. b. c.