University:
Davenport University
Course:
PHYS 210 | Fundamentals of Physics I
Academic year:

2024
Views:

67

Pages:

2
Author:

Arielle Armstrong

Name Date WORKSHEET Class MATH S KILLS U SED MATH IN SCIENCE: P HYSICAL SCIENCE Work and Power Use the equations for work and power. Part 1: An Equation for Work As you sit and read this worksheet, are you doing work? You might say, “Yes, of course.” But are you doing work in the scientiﬁc sense? Scientists use the word work to describe a very speciﬁc concept. In physics, work is a force applied over a distance. EQUATION: work Force distance WFd The SI unit for work is the newton-meter (N m), also known as a joule ( J). You can calculate the amount of work accomplished with the equation above. Let’s see how it’s done! SAMPLE PROBLEM: How much work is done on a 16 N sack of potatoes when you lift the sack 1.5 m? W 16 N 1.5 m W 24 J Work It Out! Based on what you know about work, answer the following questions. Be sure to show your work. 1. A deﬂated hot-air balloon weighs a total of 8000 N. Filled with hot air, the balloon rises to a height of 1000 m. How much work is accomplished by the hot air? 8000 N 1000 m 8,000,000 J 2. A rope is thrown over a beam, and one end is tied to a 300 N bundle of lumber. You pull the free end of the rope 2 m with a force of 400 N to lift the lumber off the ground. How much work have you done? 400 N 2 m 800 J 3. A 150 N boy rides a 60 N bicycle a total of 200 m at a constant speed. The frictional force against the forward motion of the bicycle equals 35 N. How much work does the boy do? Explain your answer. (Hint: Remember that work is only done when the motion is in the same direction that the force is applied.) 35 N 200 m 7000 J; The weights of the boy and the bicycle are not used to calculate the work done because the direction of their forces (downward) is different than the direction of the motion (forward). Name Date Class Work and Power, continued Part 2: Work and Power Work is closely related to the concept of power. Power is a measure of how much work is done in a certain time. The faster work is done, the more power is produced. work power time EQUATION: W P t The unit for power is the watt (W). One watt (W) is equal to 1 J of work done for 1 second. Use the data given in the diagram below to determine how much work and power are involved in each step. Remember to show your work. Step 1: A 50 N girl climbs the ﬂight of Force necessary to lift painting = 60 N Height of ladder = 2 m Height of stairs = 3 m stairs in 3 seconds. Work 50 N 3 m 150 J Power 150 J 3 s 50 W Step 2: The girl lifts a painting to a Step 3: The girl climbs the ladder with height of 0.5 m in 0.75 seconds. the painting in 5 seconds. Work 60 N 0.5 m 30 J Work 50 N 60 N 110 N 110 N 2 m 220 J Power 30 J 0.75 seconds 40 W Power 220 J 5 seconds 44 W Challenge Yourself! 4. A crane lifts a load of steel that weighs 9.3 105 N a distance of 100 m. It takes 5 minutes to complete the task. a. How much work is done by the crane? (9.3 105 N) 100 m 9.3 107 J, or 93,000,000 J b. How much power does the crane produce? (9.3 107 J) 300 seconds 3.1 105 W, or 310,000 W

Work and Power Worksheet

Related Documents

Recommended Documents

Description

Related Documents

Free up your schedule!

Take 5 seconds to unlock