Test Corrections(2nd Nine Weeks Exam)

Test Corrections(2nd Nine Weeks Exam)

Go through the presentation look at the examples and answering the questions. Each correct question will add 5 points to your test.

TEKS 5B: Universal Gravitation

Use the formula $F_{g_{ }}=\frac{Gm_1m_2}{d^2}\ \$  

 $G=6.67x10^{-11}$   $m_1=mass\ of\ first\ object\$  
 $m_2=mass\ of\ \sec ond\ object\$  
 $d=dis\tan ce$  

Example: Calculate the Fg(force of gravity) between two objects, one object with m1=500kg, and the other with m2=250kg. The distance between them is 50 meters.

 $F_g=\frac{\left(6.67x10^{-11}\right)\left(500\right)\left(250\right)}{\left(50\right)^2}=\frac{8.3x10^{-6}}{2500}=3.32x10^{-9}$  

Multiple Choice

Calculate the Fg between one object with m1=200kg, m2=500kg and the distance between them is 35 meters.

 $F_g=\frac{Gm_1m_2}{d^2}\ \ \ \ \left(G=6.67x10^{-11}\right)$  

• 3.7x10⁴

• 5.4x10^-9

• 2.3x10⁸

• 1.5x10^-3

TEKS 4D: Newton's Laws of Motion

Force = mass x acceleration (F=ma)

Example: Calculate the force that a truck contains if it has a mass of 1700 kg and its accelerating at 12 m/s². (F=ma)

F=(1700)(12)=20400 N

Multiple Choice

Calculate the force that a truck contains if it has a mass of 2700 kg and its accelerating at 24 m/s². (F=ma)

• 32,000 N

• 24,000 N

• 3500 N

• 64,800 N

TEKS 6A: Work Energy Theorem

Example: A bike has a force of 1200 N and travels 16 meters. Determine the work the bike does. Work=Force x Distance (W=Fd)

W=(1200)(16)=19200 J

Multiple Choice

A bike has a force of 2200 N and travels 20 meters. Determine the work the bike does. Work=Force x Distance (W=Fd)

• 23000 J

• 12000 J

• 44000 J

• 34500 J

TEKS 6B: Kinetic/Potential Energy

Example: An arrow with a mass of 2 kg is shot through the air. If the arrow is shot 25 meters into the air what is the arrow’s potential energy?

 (PE=mgh) (Potential Energy=mass x gravity x height)

PE=(2 kg)(10 m/s)(25 m)= 500 J

Multiple Choice

If an arrow has a mass of 1.2 kg is shot straight up a distance of 25 meters what is the arrow’s potential energy? PE=mgh (g=10 m/s²)

• 300 J

• 100 J

• 50 J

• 200 J

TEKS 6C: Mechanical Energy & Power

A runner at the start of a race accomplishes 2500 joules of work. If the runner completes their run in 15 seconds, how much power did they generate during this time period? 

 $Power=\frac{Work}{time}\ \ \ \ \ \ \ \ P=\frac{W}{t}=\frac{2500\ }{15}=166.7\ Watts$  

Multiple Choice

A runner at the start of a race accomplishes 3000 joules of work. If the runner completes their run in 30 seconds, how much power did they generate during this time period? 

 $P=\frac{W}{t}\ \ \ \ Power=\frac{Work}{time}$  

• 45 Watts

• 80 Watts

• 100 Watts

• 20 Watts

TEKS 6D: Conservation of Energy

TEKS 6D: Conservation of Energy

Based on the picture, which point would have the greatest potential energy?

Answer is A because it is at the highest point.

Multiple Choice

Based on the picture, which point would have the least potential energy?

• G

• C

• F

• D