Work
The formula for work
What is W= F x d?
Power is the amount of ___________ done in a certain amount of _______.
What is work; time?
You are pushing against a house. Are you doing work? Why or why not?
No because the house is not moving in the direction of the force
The unit for work
What is Newtons x Meters Joules (J)?
You use 6N to move a table 5m. How much work did you do? *Make sure to include units!
30J
A toy car was using 600J of work over 200s. What was the power of the car?
What is 3W?
Brushing your hair. Is work being done? Why or why not?
What is yes because your hair is going in the direction of your brush?
While you are riding a bicycle 5 m down the road you do 500J of work. What force did you use? *Make sure to include units!
What is 10N?
A kite was flying in the sky for 5s with a power of 10W. What is the kite's work?
What is 50J?
Two toddlers were racing to get a cookie. Toddler A got to the cookie first. Toddler B was two steps behind him. Who had more power? Why?
What is Toddler A because he got to the cookie first; he did the work in a shorter amount of time?
How do you know when work is being done?
What is when a force is applied, and the object moves in the same direction as the applied force
A football player, weighing 1500N, is traveling down the field doing 3000J of work. How far did he travel?
What is 2 m?
If you run a motor with 26000 J of work for 30 seconds. How many 60 Watt light bulbs could you light?
=866.67 Watts. 866.67/60 watts light bulb= 14.44
SO 14 light bulbs
A dog used 200J of work to create a power of 2W while running in the yard. How long did the dog run for?
What is 100s?
In a game of tug of war, Team A and Team B had equal forces. Which team did work? How do you know?
Neither team did work because the rope did not move in either direction since the forces were equal
You are at library. You pick books off the bottom shelf and bring them to waist level. You then carry the books to the check out counter. When is work being done on the books?
What is when you pick up the books from the bottom shelf?
A 8kg (what do you do with the kg?) cat on Earth climbed up a tree 4m high. How much work was done by the cat? *Make sure to include units; round to the nearest hundredth!
What is 313.6J?
Two women are running a 5k. They both reach the finish line, but runner A finishes in 45min and runner B finishes in 1hr. Which one has more power? Why?
Runner A because she did the same amount of work as Runner B but in less time
A soccer ball, weighing 10N, was kicked 20m in 50 sec. How much power does the ball have?
(10N x 20m = 200J/50s)
4W
A 100N person walked up a staircase that was 5m high in 10s. That same 100N person ran up a staircase that was 5m high in 5s. When did the person do more work? When did the person use more power? Why/Why not?
Both times the person did the same amount of work; the person used more power when they ran up the staircase bc they completed the same work quicker?