<span>Power is measured in watts. A watt is the power that it takes to do one joule ofwork in one second. It can be found using the formula <span>P=<span>Wt</span></span>. (In this formula, W stands for "work.")</span><span><span>Large amounts of energy can be measured in kilowatts (<span>1kW=1×<span>103</span>W</span>), megawatts (<span>1MW=1×<span>106</span>W</span>), or gigawatts (<span>1GW=1×<span>109</span>W</span>).</span><span><span> This is helpful</span><span> This is confusing</span></span></span><span>The watt is named James Watt, who invented an older unit of power: the horsepower.</span>
Answer:
A simple pulley is a wheel with a rope that allows you to pull one end and have it lift whatever is on the other end. A modern, common example of this is a crane, often used in construction.
Explanation:
Work = (force) x (distance)
Work = (21 Newtons) x (9 meters) = 189 Joules
Power = (work done) / (time to do the work)
Power = (189 Joules) / (3 sec)
Power = (63 watts/sec)
Power = 63 watts (D)
1 hour for the train to travel 17,000 feet