3. Final Jeopardy Question Final Jeopardy Question Energy 500 100 200 300 400 Gravity 500 400 300 200 100 Forces 500 400 300 200 100 Mix 100 200 300 400 500

4. A 10kg ball is dropped from a height of 5m. It lands on a spring (k=100N/m). 175 J are lost as friction in the fall. When the ball is moving 5m/s, how far is the spring compressed? Back GPE before hand = 10kg*10m/s/s*5m = 500J TE = 500J – 175J = 325J KE after = ½ 10kg (5m/s) 2 = 125J SPE after = 325J – 125J = 200J 200J = ½ * 100N/m (x) 2 X 2 = 200J / 50N/m = 4m 2 X = 2m

5. A 20kg ball is moving 20m/s when it rolls up a hill. How far up the hill does the ball make it? Back KE = ½ 20kg * (20m/s) 2 = 4000J GPE after = 4000J = 20kg * 10m/s/s * h h= 4000J/(20kg*10m/s/s) h = 4000J/200kgm/s/s h= 20m

6. A 5kg ball is falling 10m/s at a height of 12 m and lands on a spring (k=150N/m). How far does the spring compress? Back KE = ½ * 5kg * (10m/s) 2 = 250J GPE = 5kg * 10m/s/s * 12m = 600J Total energy = 850J SPE = 850J = ½ 150N/m (x) 2 X 2 = 850J / 75N/m = 11.33 m2 X= 3.36m

7. A 15kg ball is compressed in a spring (k=100N/m) 3m. How high in the air will the ball make it? Back SPE = ½ 100N/m (3m) 2 = 450J GPE = 450J = 15kg * 10m/s/s * h h = 3m

8. A 10kg ball is at a height of 50m and moving 10m/s. How much total energy does it have? Back TE = KE + GPE = ½ * 10kg * (10m/s) 2 + 10kg * 10m/s/s * 50m 500J + 5000J = 5500J

9. Back A scale records 100kg person’s weight on an elevator as being 200N. Which direction and at what rate is the elevator accelerating? Fdown = 100kg* 10m/s/s = 1000N Fup = 200N Fnet = 800N down A = Fnet/m = 800N/100kg = 8m/s/s down

10. A 75kg person is accelerating upwards on an elevator 4m/s/s. What weight would a scale say they weigh? Back Fnet = m*a = 75kg * 4m/s/s = 300N up Fdown = 75kg*10m/s/s = 750N Fup = 1050N

11. Back A 20kg mass is hanging (not accelerating) from a spring (k=200N/m). How far does the spring stretch? Fdown = 20kg*10m/s/s = 200N Fup = 200N = 200N/m * x X = 1m

12. A mass is stretching a spring (k=175N/m) 2m. What must be its mass? Back Fup = 175N/m * 2m = 350N Fdown = 350N = 10m/s/s * m m = 35kg

13. Draw the FBD for a 10kg mass stretching a spring Back

14. You have 4x as much mass as normal, but are 3x as far from the center of the Earth. What happens to the force of gravity 4x as much because of your mass, but 1/9 th because of your distance So 4/9ths Back

15. The acceleration of a 5kg person on Planet Physics is 100m/s/s. What is the weight of a 20kg dog on Physics Back Weight = Fg = m * g = 20kg * 100m/s/s = 2000N

16. Back Any object on Physics will accelerate at a greater rate Planet Physics is 3x as big as Earth. Which accelerates at a greater rate, a 30kg mass on Earth, or a 10kg mass on Physics?

17. An object has a weight of 30N. What is the mass? Back 30N/10m/s/s = 3kg

18. A satellite is twice the distance from the center of the Earth. What is it’s acceleration? 10m/s/s /4 = 2.5m/s/s Back

19. A 5kg mass is accelerating downwards 5m/s/s while attached to a spring (k=5N/m). How far is the spring stretched? Back Fnet = 5m/s/s * 5kg = 25N down Fg = 5kg *10m/s/s = 50N down Fs = 25N up 25N = 5N/m*x X = 5m

20. An 5kg object stretches a spring (k=40N/m) 5m. Which way and at what rate does the object accelerate? Back Fup = 40N/m * 5m = 200N Fdown = 5kg * 10m/s/s = 50N Fnet = 150N up a = 150N/5kg = 30m/s/s

21. A 5kg object stretches a spring 5m. What is the spring constant? How much SPE does the object have? Back K = F/x = 5kg*10m/s/s / 5m = 10N/m SPE = 1/2kx 2 = ½ 10N/m * (5m) 2 SPE = 125J

22. A 5kg object is on top of a 10m hill. At the bottom it is moving 10m/s/s. How much energy was lost as friction? Back GPE = 5kg * 10m/s/s * 10m = 500J KE at bottom = ½ 5kg * (10m/s) 2 = 250J Energy lost = 250J

23. What does it mean to have a large spring constant? Back It takes a large force to stretch the spring

24. Name and define as many physics terms from this unit as you can Force, GPE, KE, SPE, Spring Force, Weight, Mass, Acceleration, Net Force, Velocity, Spring Constant, Gravity, Conservation, etc. Back