Unit+6+Conservation+of+Energy+and+Momentum

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Mouse trap car tutorial

[|Mechanical Energy Quizlet]

Complete the following problems in your composition book **__ Physics 11 - Work, Power, Energy Worksheet __** 1. Calculate the work done by a 47 N force pushing a pencil 0.26 m.

2. Calculate the work done by a 47 N force pushing a 0.025 kg pencil 0.25 m against a force of 23 N.

3. Calculate the work done by a 2.4 N force pushing a 400 g sandwich across a table 0.75 m wide.

4. How much work is it to lift a 20 kg sack of potatoes vertically 6.5 m? Pay attention to the units... remember that weight is mass X gravity

5. If a small motor does 520 J of work to move a toy car 260 m, what force does it exert?

6. A girl pushes her little brother on his sled with a force of 300 N for 750 m. How much work is this if the force of friction acting on the sled is (a) 200 N, (b) 300 N?

7. What is the gravitational potential energy of a 61.2 kg person standing on the roof of a 10-storey building relative to (a) the tenth floor, (b) the sixth floor. (Each storey is 2.50 m high.)

8. A 10 000 kg airplane lands, descending a vertical distance of 10 km while travelling 100 km measured along the ground. What is the plane's loss of potential energy? (hint-- draw a picture if you are stuck)

9. A coconut falls out of a tree 12.0 m above the ground and hits a bystander 3.00 m tall on the top of the head. It bounces back up 1.50 m before falling to the ground. If the mass of the coconut is 2.00 kg, calculate the potential energy of the coconut relative to the ground at each of the following sites:

(a) while it is still in the tree, (b) when it hits the bystander on the head, (c) when it bounces up to its maximum height, (d) when it lands on the ground, (e) when it rolls into a groundhog hole, and falls 2.50 m to the bottom of the hole.

10. Calculate the kinetic energy of a 45 g golf ball travelling at: (a) 20 m/s, (b) 40 m/s, (c) 60 m/s.

11. When the speed of an object doubles, does its kinetic energy double? Using complete sentences, explain your answer.

12. How fast must a 1000 kg car be moving to have a kinetic energy of: (a) 2.0 x 10^3 J, (b) 2.0 x 10^5 J

13. How high would you have to lift a 1000 kg car to give it a potential energy of: (a) 2.0 x 10^3 J, (b) 2.00 x 10^5 J

14. A 50 kg bicyclist on a 10 kg bicycle speeds up from 5.0 m/s to 10 m/s. (a) What was the total kinetic energy before accelerating? (b) What was the total kinetic energy after accelerating? (c) How much work was done to increase the kinetic energy of the bicyclist? (d) Is it more work to speed up from 0 to 5.0 m/s than from 5.0 to 10.0 m/s?

15. At the moment when a shotputter releases a 5.00 kg shot, the shot is 3.00 m above the ground and travelling at 15.0 m/s. It reaches a maximum height of 8.00 m above the ground and then falls to the ground. If air resistance is negligible, (a) What was the potential energy of the shot as it left the hand relative to the ground? (b) What was the kinetic energy of the shot as it left the hand? (c) What was the total energy of the shot as it left the hand? (d) What was the total energy of the shot as it reached its maximum height? (e) What was the potential energy of the shot at its maximum height? (f) What was the kinetic energy of the shot at its maximum height? (g) What was the kinetic energy of the shot just as it struck the ground?

-- complete in composition notebook. Answer questions using complete sentences.

[|skate park simulation]

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