A battery is connected to a small, noisy heater (it makes sound). During a certain period of time after the heater has reached its operating temperature, the battery transfers 10 joules of energy to the heater due to an electric circuit interaction and transfers 0.4 joules of energy to the surroundings due to heat interactions. During that same time period, the heater transfers 8 joules of energy to the surroundings due to heat interactions and transfers 2 joules of energy to the sound receivers due to a sound interaction. What is the efficiency of the heater

Askydiver weighing 140 lb (including equipment) falls vertically downward from an altitude of 19,000 ft and opens the parachute after 18 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.55|v| when the parachute is closed and is of magnitude 14|v| when the parachute is open, where the velocity v is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. (a) find the speed of the skydiver when the parachute opens. (b) find the distance fallen before the parachute opens. (c) what is the limiting velocity vl after the parachute opens? (d) determine how long the sky diver is in the air after the parachute opens. (e) plot the graph of velocity versus time from the beginning of the fall until the skydiver reaches the ground.

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

How do the kidneys affect homeostasis