A string going over a massless frictionless pul- ley connects two blocks of masses 4.2 kg and
3.8 kg. As shown on the picture below, the
4.2 kg block lies on a 23° incline; the coefli-
cient of kinetic friction between the block and
the incline is u= 0.23. The 3.8 kg block is
hanging in the air.
The 3.8 kg block accelerates downward
while the 4.2 kg block goes up the incline
with the same acceleration.
If gravity is constant (g=9.8), what is the acceleration of the system?

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

Will give brainliest! jay rides his 2.0-kg skateboard. he is moving at speed 5.8 m/s when he pushes off the board and continues to move forward in the air at 5.4 m/s. the board now goes forward at 13 m/s. a. determine jay’s mass. b. determine the change in the internal energy of the system during this process.(express your answer to two significant figures and include the appropriate units.)

Acamcorder has a power rating of 20 watts. if the output voltage from its battery is 9 volts, what current does it use?