What is meant by action and reaction

Ellen needs to move a heavy box across the floor and then place it on a shelf that is four feet above the floor. Which use of machines would most likely require the least amount of force in order to get the box on the shelf? A.

Which of the following is the most likely reason that a population might crash?

Without Newton's third law of motion, what would an object sitting on a table do?

When is systolic pressure measured? When is diastolic pressure measured?

An automobile engine has an efficiency of 19.0%. If it produces 23.0 kJ of mechanical work per second, the heat rejected per second from the engine is closest to: (a) 77.0 kJ (b) 81.5 kJ (c) 86.5 kJ (d) 92.0 kJ (e) 98.1 kJ

An olympic hurdler accelerates at a rate of 15.5 m/s2. what is the rate in miles/min2?

What is the conservation of energy?

What data are needed to calculate the actual mechanical advantage of a machine

What antenna length should be used to create a dipole antenna that emits 100-mhz electromagnetic waves, a frequency typical of fm radio broadcasts?

If a motor lifts a 400.-kilogram mass a vertical distance of 10. meters in 8.0 seconds, the minimum power generated by the motor is (1) 3.2 * 10^2 W (3) 4.9 * 10^3 W (2) 5.0 * 10^2 W (4) 3.2 * 10^4 W