Practice 1. Which of the following represents the relationship between work, power, and time? Choices P = W/t W = P/t P = W×t t = W×P 2.  A machine does 2500 J of work in 1 min. What is the power developed by the machine? Choices 21 W 42 W 150 W 2500 W 3. What is the average power output of a weightlifter who can lift 250 kg weights 2.0 m in 2.0 s? Choices 2.5 kW 5.0 ×  102 W 4.9 kW 9.8 kW

Q: 3. A boy pulls a 27.0-kg box with a 170-N force at 33° above a horizontal surface. If the…

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Q: 1. For exercise, an athlete lifts a barbell that weighs 400 N from the ground to a height of 2.20 m…

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Q: 16. A diesel-powered crane (mc = 2.93 x 10° kg) is lifting a heavy block of concrete mb = 8.44 x 104…

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Q: An elevator weighing 3000N ascends at a constant speed of 8.omis. How much power must the motor…

A: Given : Force (F) = 3000 N Speed (v) = 8.0 m/s

Q: A57 g plastic ball is moving to the left at 14 m/s. How much work must be done on the ball to cause…

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Q: The acceleration of a 2.00 kg object is shown below. If as=6.0 m/s2, and the object starts from…

A: Mass of object (m) = 2 kg The value of as = 6 ms2initial velocity of object (u)= 0 msLet final…

Q: How much work is needed to change the speed of a 2375 kg sport utility vehicle from 15.0 m/s to 60…

A: Given data:  Mass (m) = 2375 kg Initial velocity (Vi ) = 15.0 m/s Final velocity (Vf) = 60 m/s…

Q: Six dogs pull a two-person sled with a total mass of 220 kg. The coefficient of kinetic friction…

A: The free body diagram is as follows,

Q: A ski area claims that its lifts can move 48,000 people per hour. a.)If the average lift carries…

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Q: A box is being pushed to the right with 112N of force. The box travels a total of 1.5m to the right.…

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Q: A box of mass 4.0 kg hangs by a cable from the ceiling of an elevator. The elevator is moving up at…

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Q: tion F(x) = ax2 - bx, where a = 65 N/m2, b = 18 N/m, and the positive x direction is in the…

A: GivenF(x)=ax2-bxwherea=65 N/m2b=18 N/m

Q: A 7.5-kg otter slides down a mud bank, starting from rest at the top. The sloping surface of the…

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Q: There is a 100 kg box that starts at rest. a person pushes that box over the course of 18 meters…

A: Given mass of box m = 100 kg initial speed u = 0 m/s final speed v = 10 m/s displacement x = 18 m…

Q: The power output (in W) needed from a motor to lift a mass of 1.5 x 104 Kg, 25 m in 6.0 s at…

A: The mass is The displacement of the mass is The lifting time is

Q: Consider the net work required to stop a moving object. a. What is the net work, in joules,…

A: Given data:  Mass (m) = 60.4 kg Initial velocity (u) = 1.96 m/s Final velocity (v) = 0 m/s Required:…

Q: The energy stored in a spring is 20 J when it is stretched to 5cm. How much energy is stored when it…

A: Given data: Energy stored in spring (U) = 20 J Stretch in spring (x) = 5 cm New stretch in spring…

Q: Consider the net work required to stop a moving object. a. What is the net work, in joules,…

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Q: 1. Emma pushes a 45.0kg box across a level floor with an applied force of 155N [30° above…

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Q: There is a 23.1 kg box that starts with an initial velocity of 23.5 m/s. The box moves up a hill…

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Q: A 5.00 gram bullet moving horizontally with a speed of 400 m/s collides with a wooden block. After…

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Q: A box of mass 4.0 kg hangs by a cable from the ceiling of an elevator. The elevator is moving down…

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Q: You push a file cabinet up a frictionless ramp tilted at 10°with horizontal. The file cabinet has a…

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Q: 45. A 20 kg crate slides down a 10 m high 30 degree incline with a frictional coefficient of .100.…

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Q: Power of the Human Heart. The human heart is a powerful and extremely reliable pump. Each day it…

A: Given: The volume of the blood is 7500 L. The height lifted to blood is 1.5 m. The density of the…

Instantaneous Power

Power is defined in physics as the amount of energy transmitted or transformed per unit time. The watt is the unit of electricity in the International System of Units, equivalent to one joule per second.