Acrowbar is used as a lever. the effort force of 40 newtons moves 3 meters. the resistance force of 54 newtons moves 2 meters. what is the efficiency of the lever? 100% because energy must be conserved 90% 25% 18%

Which diagram correctly demonstrates the various forces acting on a ball moving horizontally with some speed?

Who was the first scientist to measure speed as distance over time?

Two resistors r1 and r2 may be connected either in series or parallel across an ideal battery with emf ε. we desire the rate of energy dissipation of the parallel combination to be 8.75 times that of the series combination. if r1 = 105 ω, what are the (a) smaller and (b) larger of the two values of r2 that result in that dissipation rate?