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Question :
66. The unit of power, watt, dimensionally the same as:
A. : 2102112

66. The unit of power, watt, is dimensionally the same as:

A. joule-second.

B. joule/second.

C. joule-meter.

D. joule/meter.

67. A 60-kg woman runs up a flight of stairs having a rise of 4.0 m in a time of 4.2 s. What average power did she supply?

A. 380 W

B. 560 W

C. 620 W

D. 670 W

68. An automobile delivers 30.0 hp to its wheels when moving at a constant speed of 22.0 m/s. What is the resistance force on the automobile at this speed? (1 hp = 746 watts)

A. 18 600 N

B. 410 000 N

C. 1 020 N

D. 848 N

69. Yuri, a Russian weightlifter, is able to lift 250 kg 2.00 m in 2.00 s. What is his power output?

A. 500 W

B. 2.45 kW

C. 4.90 kW

D. 9.80 kW

70. A jet engine develops 1.0 ยด 10^{5} N of thrust in moving an airplane forward at a speed of 900 km/h. What is the power developed by the engine?

A. 500 kW

B. 10 MW

C. 25 MW

D. 50 MW