Power and Work

A weightlifter lifts two 300 newton weights 1.5 meters off the ground. How much work has he done?

• 600 J 

• 660 J

• 900 J 

• 1200 J 

You do 90 joules of work in 30 seconds. How much power have you generated?

• 30 watts

• 3 watts

• 120 watts

• 270 watts

You move an 8-newton weight five meters in 4 seconds. How much power have you generated?

• 160 watts

• 10 watts

• 6.4 watts

• 17 watts

Which of the following would produce the most power?

• mass of 10 kilograms lifted 10 meters in 10 seconds 

• mass of 10 kilograms lifted 10 meters in 5 seconds

• mass of 5 kilograms lifted 10 meters in 5 seconds

• mass of 5 kilograms lifted 5 meters in 10 seconds

Chad’s family just moved into a new home. The sun went down as Chad was moving boxes into the house, so he had to turn on a light to see. Which statements are true about the power Chad used? Choose the two statements that apply.

• The power he used to move the boxes can be found by determining the rate at which work was done on the boxes.

• The power Chad used to move the boxes is the force he used times the distance he moved them

• The power of the light Chad turned on is the amount of energy changed from electricity to light.

• The power of the light Chad turned on is the amount of energy transferred per time.

Tags

NGSS.MS-PS2-2

The rate at which work is done is ____.

• power

• force

• efficiency

• momentum

9, 000 N is the bite force of one adult American alligator. Assuming it has a bite distance of 0.5 m and is biting within 0.25 seconds, how much power does it bite with?

Fill in these steps. First find work (w=fd) by multiplying ​ (a)   by ​ (b)   . That gives you 4500. Divide that by ​ (c)   to calculate power . Answer: (d)  

• 18,000 J/s or Watts

• 4,500 J/s or Watts

• 9000

• 0.5

• 0.25

​ (a)   is how much work is done in a certain amount of time

• Power

• Work

• Speed

• Velocity

• Acceleration

Chad’s family just moved into a new home. The sun went down as Chad was moving boxes into the house, so he had to turn on a light to see. Which statements are true about the power Chad used? Choose the two statements that apply.

• The power he used to move the boxes can be found by determining the rate at which work was done on the boxes.

• The power Chad used to move the boxes is the force he used times the distance he moved them

• The power of the light Chad turned on is the amount of energy changed from electricity to light.

• The power of the light Chad turned on is the amount of energy transferred per time.

Which of the following is a true statement about work?

• It measures how quickly an object accelerates 

• It measures how much effort is applied over a certain distance

• It measures the change in an object's rate of speed

• It measures how much time it takes to move a massive object

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5