The area under the force vs. displacement curve represents:
a. area.
b. force.
c. work.
d. coefficient of static friction.
[Ques. 2] Water flows over a section of Niagara Falls at a rate of 1.30 106 kg/s and falls 52.0 m. What is the power dissipated by the waterfall?
a. 6.6E+8 W
b. 6.8E+7 W
c. 4.0E+7 W
d. 5.3E+8 W
e. 8.6E+6 W
[Ques. 3] Motor 1 does 30 J of work in 10 s, motor 2 does 2 J of work in 5 s, motor 3 does 7 J of work in 2 s, and motor 4 does 7 J of work in 3 s. List the motors in order of highest power produced to lowest power produced.
a. 2, 4, 1, 3 b. 3, 4, 1, 2
c. 1, 3, 4, 2 d. 3, 1, 4, 2
[Ques. 4] A 100-W light bulb is left on for 8.0 hours. Over this period of time, how much energy was used by the bulb?
a. 8.0E+2 J
b. 2.9E+5 J
c. 2.9E+6 J
d. 1.34 hp
e. 2.9E+4 J
[Ques. 5] A force of 5.0 N is applied to a 20-kg mass on a horizontal frictionless surface. As the speed of the mass increases at a constant acceleration, the power delivered to it by the force:
a. remains the same.
b. increases.
c. decreases.
d. doubles every 4.0 seconds.
[Ques. 6] A 1 000-kg sports car accelerates from zero to 25 m/s in 7.0 s. What is the average power delivered by the automobile engine?
a. 8.9E+4 W
b. 1.8E+3 W
c. 4.5E+4 W
d. 1.8E+5 W
e. 5.4E+4 W
[Ques. 7] A speed boat requires 85.0 kW to move at a constant speed of 14.0 m/s. What is the resistive force of the water at this speed?
a. 1 190 N
b. 6 070 N
c. 6 170 N
d. 5 970 N
e. 1 290 N
[Ques. 8] A jet engine develops 1.50 105 N of thrust in moving an airplane forward at a speed of 900 km/h. What is the power developed by the engine?
a. 1 350 kW
b. 380 MW
c. 37.5 MW
d. 42.5 MW
e. 32.5 MW
[Ques. 9] Yuri, a Russian weightlifter, is able to lift 260 kg 2.10 m in 2.20 s. What is his power output?
a. 546 W
b. 2.43 kW
c. 1.21 kW
d. 11.8 kW
e. 24.3 kW
[Ques. 10] An automobile delivers 30.0 hp to its wheels when moving at a constant speed of 24.0 m/s. What is the resistance force on the automobile at this speed? (1 hp = 746 watts)
a. 5.37E+5 N
b. 1.21E+3 N
c. 9.33E+2 N
d. 3.73E+2 N
e. 5.97E+2 N
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