Urgent
science

what are significant figures ?

(a) they are all known digits in a measurement

(b) the gauge of the accuracy of a measurement

(c) the limit of a measurement

(d) they are a close approximation of the actual value of what is being measured

1.in one challenge on the titan games, competitors have to lift 200 pounds up a long ramp. angel is able to move the weight in 42 seconds. anthony gets it done in only 38 seconds. which statement is true? angel has more power than anthony. angel does more work than anthony. anthony does more work than angel. anthony has more power than angel. 2.a mountain climber exerts 41,000 j of work to climb a cliff. how much power does the climber need if she wants to finish in only 500 seconds? power = work / time 20,500,000 watts 82 watts 0.0122 watts 41,500 watts 3.your family is moving to a new apartment. while lifting a box 83 joules of work is done to put the box on a truck, you exert an upward force of 75 n for 3 s. how much power is required to do this? (hint: you only need two of the 3 numbers given! ) power = work / time 249 watts 25 watts 2075 watts 27.7 watts

Friction removes energy from objects in motion. which statement best describes how this works? a) friction transforms ke into thermal energy b) friction transfers thermal energy to ke c) friction transforms te into pe d) friction transforms pe into ke e) friction transfers ke into pe

List and describe three ways that humans can change ecosystems and three ways that humans can protect ecosystems.