Answer:
4
Explanation:
The weight of the rock is W = mg = (80 kg) (10 m/s²) = 800 N.
The mechanical advantage is therefore 800 N / 200 N = 4.
Answer:
Resistance, 
Explanation:
Given that,
Voltage of the battery, V = 9 volts
Current produced in the circuit, I = 17 A
We need to find the resistance when shorted by a wire of negligible resistance. It is a case of Ohm's law. The voltage is given by :




So, the resistance in the circuit is 0.529 ohms. Hence, this is the required solution.
Answer:
glass if for a good view, but for absorbing heat concrete and brick is the best
Explanation:
wood is not a good idea bc it can cause fires from too much heat and it absorbs less heat but all of that depends on how good the material your using
Answer:

Explanation:
= Angular speed
= Distance of Mary = 11.5 ft
= Distance of Alex = 6 ft
Ratio of centripetal acceleration is given by

Mary's centripetal acceleration is 1.92 times the centripetal acceleration of Alex
Answer:
Insulation helps to prevent that transfer of heat.