What determines whether or not work is being done?

An open train car, with a mass of 2130 kg, coasts along a horizontal track at the speed 2.93 m/s. The car passes under a loading chute and, as it does so, gravel falls vertically into it for 3.03 s at the rate of 465 kg/s.

The density of air under normal conditions is about 3 1.2 kg / m. For a wind speed of 10 m/s, find (a) the actual power carried in the wind; (b) the maximum power (Betz limit) extractable by a wind turbine with a blade area of 10 m2;

What will be the effect of two forces of equal magnitude acting on a moving rigid body from opposite directions along the same line? a) the object will deform. b) the object will twist or turn. c) the object will remain in static equilibrium.

Which of these best shows a change from potential to kinetic energy? A Water flowing over a tall cliff B A metal spring being stretched C Electricity making a bulb light up D A stone lying on top of a mountain

Two identical speakers separated by 14.9 m are driven by the same oscillation with a frequency of 26.3 Hz. x y b (x, y) b 1 st A 2 nd 14.9 m Find the distance from the first speaker to a receiver at A if it records a minimum in sound intensity.

In a scientific experiment, the_ changes in response to another change. O O A. hypothesis B. conclusion O O O C. dependent variable O D. independent variable

How do animals affect the amount of carbon in earth's atmosphere

A 1600-kg car travels at a speed of 12.5m/s what is its kinetic energy

I'm hooke's law F=kx, what does the k stand for

The temperature of an object increases by 30.2 °c when it absorbs 3715 j of heat. calculate the heat capacity of the object.