Penn Physical Science Lesson 1 700169RR/Penn Physical Science Lesson 1 700169RR

Penn Physical Science Lesson 1 700169RR




Question

Question 1

1. If a stone with an original velocity of 0 is falling from a ledge and takes 8 seconds to hit

the ground, what is the final velocity of the stone?

A. 78.4 m/s

B. 39.2 m/s

C. 156.8 m/s

D. 42.6 m/s

v = gt = (9.81 m/s²)(8s) = 78.4 m/s

Question 2

2. Your boss tells you that she needs a decision by the end of the day about the machine you

want to purchase for your new operation. You have four options, and your boss reminds you

to be as cost-efficient as possible but that she also wants the best efficiency. Which is your

best option?

Option 1: This $5,000 machine is supplied energy at a rate of 1,900 W and does useful work

at a rate of 1,786 W.

Option 2: This $4,500 machine is supplied energy at a rate of 1,450 W and does useful work

at a rate of 1,300 W.

Option 3: This $4,750 machine is supplied energy at a rate of 1950 W and does useful work

at a rate of 1833 W.

Option 4: This $4,750 machine is supplied energy at a rate of 2,000 W and does useful work

at a rate of 1,822 W.